Rajini -
I understand what you’re saying, but the point I’m making is that I don’t
believe we need to take it into account directly. The CPU utilization of
the network threads is directly proportional to the number of bytes being
sent. The more bytes, the more CPU that is required for SSL (or other
tasks). This is opposed to the request handler threads, where there are a
number of factors that affect CPU utilization. This means that it’s not
necessary to separately quota network thread byte usage and CPU - if we
quota byte usage (which we already do), we have fixed the CPU usage at a
proportional amount.
Jun -
Thanks for the clarification there. I was thinking of the utilization
percentage as being fixed, not what the percentage reflects. I’m not tied
to either way of doing it, provided that we do not lock clients to a single
thread. For example, if I specify that a given client can use 10% of a
single thread, that should also mean they can use 1% on 10 threads.
-Todd
On Wed, Mar 8, 2017 at 8:57 AM, Jun Rao <j...@confluent.io> wrote:
> Hi, Todd,
>
> Thanks for the feedback.
>
> I just want to clarify your second point. If the limit percentage is per
> thread and the thread counts are changed, the absolute processing limit for
> existing users haven't changed and there is no need to adjust them. On the
> other hand, if the limit percentage is of total thread pool capacity and
> the thread counts are changed, the effective processing limit for a user
> will change. So, to preserve the current processing limit, existing user
> limits have to be adjusted. If there is a hardware change, the effective
> processing limit for a user will change in either approach and the existing
> limit may need to be adjusted. However, hardware changes are less common
> than thread pool configuration changes.
>
> Thanks,
>
> Jun
>
> On Tue, Mar 7, 2017 at 4:45 PM, Todd Palino <tpal...@gmail.com> wrote:
>
> > I’ve been following this one on and off, and overall it sounds good to
> me.
> >
> > - The SSL question is a good one. However, that type of overhead should
> be
> > proportional to the bytes rate, so I think that a bytes rate quota would
> > still be a suitable way to address it.
> >
> > - I think it’s better to make the quota percentage of total thread pool
> > capacity, and not percentage of an individual thread. That way you don’t
> > have to adjust it when you adjust thread counts (tuning, hardware
> changes,
> > etc.)
> >
> >
> > -Todd
> >
> >
> >
> > On Tue, Mar 7, 2017 at 2:38 PM, Becket Qin <becket....@gmail.com> wrote:
> >
> > > I see. Good point about SSL.
> > >
> > > I just asked Todd to take a look.
> > >
> > > Thanks,
> > >
> > > Jiangjie (Becket) Qin
> > >
> > > On Tue, Mar 7, 2017 at 2:17 PM, Jun Rao <j...@confluent.io> wrote:
> > >
> > > > Hi, Jiangjie,
> > > >
> > > > Yes, I agree that byte rate already protects the network threads
> > > > indirectly. I am not sure if byte rate fully captures the CPU
> overhead
> > in
> > > > network due to SSL. So, at the high level, we can use request time
> > limit
> > > to
> > > > protect CPU and use byte rate to protect storage and network.
> > > >
> > > > Also, do you think you can get Todd to comment on this KIP?
> > > >
> > > > Thanks,
> > > >
> > > > Jun
> > > >
> > > > On Tue, Mar 7, 2017 at 11:21 AM, Becket Qin <becket....@gmail.com>
> > > wrote:
> > > >
> > > > > Hi Rajini/Jun,
> > > > >
> > > > > The percentage based reasoning sounds good.
> > > > > One thing I am wondering is that if we assume the network thread
> are
> > > just
> > > > > doing the network IO, can we say bytes rate quota is already sort
> of
> > > > > network threads quota?
> > > > > If we take network threads into the consideration here, would that
> be
> > > > > somewhat overlapping with the bytes rate quota?
> > > > >
> > > > > Thanks,
> > > > >
> > > > > Jiangjie (Becket) Qin
> > > > >
> > > > > On Tue, Mar 7, 2017 at 11:04 AM, Rajini Sivaram <
> > > rajinisiva...@gmail.com
> > > > >
> > > > > wrote:
> > > > >
> > > > > > Jun,
> > > > > >
> > > > > > Thank you for the explanation, I hadn't realized you meant
> > percentage
> > > > of
> > > > > > the total thread pool. If everyone is OK with Jun's suggestion, I
> > > will
> > > > > > update the KIP.
> > > > > >
> > > > > > Thanks,
> > > > > >
> > > > > > Rajini
> > > > > >
> > > > > > On Tue, Mar 7, 2017 at 5:08 PM, Jun Rao <j...@confluent.io>
> wrote:
> > > > > >
> > > > > > > Hi, Rajini,
> > > > > > >
> > > > > > > Let's take your example. Let's say a user sets the limit to
> 50%.
> > I
> > > am
> > > > > not
> > > > > > > sure if it's better to apply the same percentage separately to
> > > > network
> > > > > > and
> > > > > > > io thread pool. For example, for produce requests, most of the
> > time
> > > > > will
> > > > > > be
> > > > > > > spent in the io threads whereas for fetch requests, most of the
> > > time
> > > > > will
> > > > > > > be in the network threads. So, using the same percentage in
> both
> > > > thread
> > > > > > > pools means one of the pools' resource will be over allocated.
> > > > > > >
> > > > > > > An alternative way is to simply model network and io thread
> pool
> > > > > > together.
> > > > > > > If you get 10 io threads and 5 network threads, you get 1500%
> > > request
> > > > > > > processing power. A 50% limit means a total of 750% processing
> > > power.
> > > > > We
> > > > > > > just add up the time a user request spent in either network or
> io
> > > > > thread.
> > > > > > > If that total exceeds 750% (doesn't matter whether it's spent
> > more
> > > in
> > > > > > > network or io thread), the request will be throttled. This
> seems
> > > more
> > > > > > > general and is not sensitive to the current implementation
> detail
> > > of
> > > > > > having
> > > > > > > a separate network and io thread pool. In the future, if the
> > > > threading
> > > > > > > model changes, the same concept of quota can still be applied.
> > For
> > > > now,
> > > > > > > since it's a bit tricky to add the delay logic in the network
> > > thread
> > > > > > pool,
> > > > > > > we could probably just do the delaying only in the io threads
> as
> > > you
> > > > > > > suggested earlier.
> > > > > > >
> > > > > > > There is still the orthogonal question of whether a quota of
> 50%
> > is
> > > > out
> > > > > > of
> > > > > > > 100% or 100% * #total processing threads. My feeling is that
> the
> > > > latter
> > > > > > is
> > > > > > > slightly better based on my explanation earlier. The way to
> > > describe
> > > > > this
> > > > > > > quota to the users can be "share of elapsed request processing
> > time
> > > > on
> > > > > a
> > > > > > > single CPU" (similar to top).
> > > > > > >
> > > > > > > Thanks,
> > > > > > >
> > > > > > > Jun
> > > > > > >
> > > > > > >
> > > > > > > On Fri, Mar 3, 2017 at 4:22 AM, Rajini Sivaram <
> > > > > rajinisiva...@gmail.com>
> > > > > > > wrote:
> > > > > > >
> > > > > > > > Jun,
> > > > > > > >
> > > > > > > > Agree about the two scenarios.
> > > > > > > >
> > > > > > > > But still not sure about a single quota covering both network
> > > > threads
> > > > > > and
> > > > > > > > I/O threads with per-thread quota. If there are 10 I/O
> threads
> > > and
> > > > 5
> > > > > > > > network threads and I want to assign half the quota to userA,
> > the
> > > > > quota
> > > > > > > > would be 750%. I imagine, internally, we would convert this
> to
> > > 500%
> > > > > for
> > > > > > > I/O
> > > > > > > > and 250% for network threads to allocate 50% of each pool.
> > > > > > > >
> > > > > > > > A couple of scenarios:
> > > > > > > >
> > > > > > > > 1. Admin adds 1 extra network thread. To retain 50%, admin
> > needs
> > > to
> > > > > now
> > > > > > > > allocate 800% for each user. Or increase the quota for a few
> > > users.
> > > > > To
> > > > > > > me,
> > > > > > > > it feels like admin needs to convert 50% to 800% and Kafka
> > > > internally
> > > > > > > needs
> > > > > > > > to convert 800% to (500%, 300%). Everyone using just 50%
> feels
> > a
> > > > lot
> > > > > > > > simpler.
> > > > > > > >
> > > > > > > > 2. We decide to add some other thread to this list. Admin
> needs
> > > to
> > > > > know
> > > > > > > > exactly how many threads form the maximum quota. And we can
> be
> > > > > changing
> > > > > > > > this between broker versions as we add more to the list.
> Again
> > a
> > > > > single
> > > > > > > > overall percent would be a lot simpler.
> > > > > > > >
> > > > > > > > There were others who were unconvinced by a single percent
> from
> > > the
> > > > > > > initial
> > > > > > > > proposal and were happier with thread units similar to CPU
> > units,
> > > > so
> > > > > I
> > > > > > am
> > > > > > > > ok with going with per-thread quotas (as units or percent).
> > Just
> > > > not
> > > > > > sure
> > > > > > > > it makes it easier for admin in all cases.
> > > > > > > >
> > > > > > > > Regards,
> > > > > > > >
> > > > > > > > Rajini
> > > > > > > >
> > > > > > > >
> > > > > > > > On Fri, Mar 3, 2017 at 6:03 AM, Jun Rao <j...@confluent.io>
> > > wrote:
> > > > > > > >
> > > > > > > > > Hi, Rajini,
> > > > > > > > >
> > > > > > > > > Consider modeling as n * 100% unit. For 2), the question is
> > > > what's
> > > > > > > > causing
> > > > > > > > > the I/O threads to be saturated. It's unlikely that all
> > users'
> > > > > > > > utilization
> > > > > > > > > have increased at the same. A more likely case is that a
> few
> > > > > isolated
> > > > > > > > > users' utilization have increased. If so, after increasing
> > the
> > > > > number
> > > > > > > of
> > > > > > > > > threads, the admin just needs to adjust the quota for a few
> > > > > isolated
> > > > > > > > users,
> > > > > > > > > which is expected and is less work.
> > > > > > > > >
> > > > > > > > > Consider modeling as 1 * 100% unit. For 1), all users'
> quota
> > > need
> > > > > to
> > > > > > be
> > > > > > > > > adjusted, which is unexpected and is more work.
> > > > > > > > >
> > > > > > > > > So, to me, the n * 100% model seems more convenient.
> > > > > > > > >
> > > > > > > > > As for future extension to cover network thread
> utilization,
> > I
> > > > was
> > > > > > > > thinking
> > > > > > > > > that one way is to simply model the capacity as (n + m) *
> > 100%
> > > > > unit,
> > > > > > > > where
> > > > > > > > > n and m are the number of network and i/o threads,
> > > respectively.
> > > > > > Then,
> > > > > > > > for
> > > > > > > > > each user, we can just add up the utilization in the
> network
> > > and
> > > > > the
> > > > > > > i/o
> > > > > > > > > thread. If we do this, we don't need a new type of quota.
> > > > > > > > >
> > > > > > > > > Thanks,
> > > > > > > > >
> > > > > > > > > Jun
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > On Thu, Mar 2, 2017 at 12:27 PM, Rajini Sivaram <
> > > > > > > rajinisiva...@gmail.com
> > > > > > > > >
> > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Jun,
> > > > > > > > > >
> > > > > > > > > > If we use request.percentage as the percentage used in a
> > > single
> > > > > I/O
> > > > > > > > > thread,
> > > > > > > > > > the total percentage being allocated will be
> > num.io.threads *
> > > > 100
> > > > > > for
> > > > > > > > I/O
> > > > > > > > > > threads and num.network.threads * 100 for network
> threads.
> > A
> > > > > single
> > > > > > > > quota
> > > > > > > > > > covering the two as a percentage wouldn't quite work if
> you
> > > > want
> > > > > to
> > > > > > > > > > allocate the same proportion in both cases. If we want to
> > > treat
> > > > > > > threads
> > > > > > > > > as
> > > > > > > > > > separate units, won't we need two quota configurations
> > > > regardless
> > > > > > of
> > > > > > > > > > whether we use units or percentage? Perhaps I
> misunderstood
> > > > your
> > > > > > > > > > suggestion.
> > > > > > > > > >
> > > > > > > > > > I think there are two cases:
> > > > > > > > > >
> > > > > > > > > > 1. The use case that you mentioned where an admin is
> > > adding
> > > > > more
> > > > > > > > users
> > > > > > > > > > and decides to add more I/O threads and expects to
> find
> > > free
> > > > > > quota
> > > > > > > > to
> > > > > > > > > > allocate for new users.
> > > > > > > > > > 2. Admin adds more I/O threads because the I/O threads
> > are
> > > > > > > saturated
> > > > > > > > > and
> > > > > > > > > > there are cores available to allocate, even though the
> > > > number
> > > > > or
> > > > > > > > > > users/clients hasn't changed.
> > > > > > > > > >
> > > > > > > > > > If we allocated treated I/O threads as a single unit of
> > 100%,
> > > > all
> > > > > > > user
> > > > > > > > > > quotas need to be reallocated for 1). If we allocated I/O
> > > > threads
> > > > > > as
> > > > > > > n
> > > > > > > > > > units with n*100%, all user quotas need to be reallocated
> > for
> > > > 2),
> > > > > > > > > otherwise
> > > > > > > > > > some of the new threads may just not be used. Either way
> it
> > > > > should
> > > > > > be
> > > > > > > > > easy
> > > > > > > > > > to write a script to decrease/increase quotas by a
> multiple
> > > for
> > > > > all
> > > > > > > > > users.
> > > > > > > > > >
> > > > > > > > > > So it really boils down to which quota unit is most
> > intuitive
> > > > in
> > > > > > > terms
> > > > > > > > of
> > > > > > > > > > configuration. And from the discussion so far, it feels
> > like
> > > > > > opinion
> > > > > > > is
> > > > > > > > > > divided on whether quotas should be carved out of an
> > absolute
> > > > > 100%
> > > > > > > (or
> > > > > > > > 1
> > > > > > > > > > unit) or be relative to the number of threads (n*100% or
> n
> > > > > units).
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > On Thu, Mar 2, 2017 at 7:31 PM, Jun Rao <
> j...@confluent.io>
> > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Another way to express an absolute limit is to use
> > > > > > > > request.percentage,
> > > > > > > > > > but
> > > > > > > > > > > treat it as the percentage used in a single request
> > > handling
> > > > > > > thread.
> > > > > > > > > For
> > > > > > > > > > > now, the request handling threads can be just the io
> > > threads.
> > > > > In
> > > > > > > the
> > > > > > > > > > > future, they can cover the network threads as well.
> This
> > is
> > > > > > similar
> > > > > > > > to
> > > > > > > > > > how
> > > > > > > > > > > top reports CPU usage and may be a bit easier for
> people
> > to
> > > > > > > > understand.
> > > > > > > > > > >
> > > > > > > > > > > Thanks,
> > > > > > > > > > >
> > > > > > > > > > > Jun
> > > > > > > > > > >
> > > > > > > > > > > On Fri, Feb 24, 2017 at 10:31 AM, Jun Rao <
> > > j...@confluent.io>
> > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > Hi, Jay,
> > > > > > > > > > > >
> > > > > > > > > > > > 2. Regarding request.unit vs request.percentage. I
> > > started
> > > > > with
> > > > > > > > > > > > request.percentage too. The reasoning for
> request.unit
> > is
> > > > the
> > > > > > > > > > following.
> > > > > > > > > > > > Suppose that the capacity has been reached on a
> broker
> > > and
> > > > > the
> > > > > > > > admin
> > > > > > > > > > > needs
> > > > > > > > > > > > to add a new user. A simple way to increase the
> > capacity
> > > is
> > > > > to
> > > > > > > > > increase
> > > > > > > > > > > the
> > > > > > > > > > > > number of io threads, assuming there are still enough
> > > > cores.
> > > > > If
> > > > > > > the
> > > > > > > > > > limit
> > > > > > > > > > > > is based on percentage, the additional capacity
> > > > automatically
> > > > > > > gets
> > > > > > > > > > > > distributed to existing users and we haven't really
> > > carved
> > > > > out
> > > > > > > any
> > > > > > > > > > > > additional resource for the new user. Now, is it easy
> > > for a
> > > > > > user
> > > > > > > to
> > > > > > > > > > > reason
> > > > > > > > > > > > about 0.1 unit vs 10%. My feeling is that both are
> hard
> > > and
> > > > > > have
> > > > > > > to
> > > > > > > > > be
> > > > > > > > > > > > configured empirically. Not sure if percentage is
> > > obviously
> > > > > > > easier
> > > > > > > > to
> > > > > > > > > > > > reason about.
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks,
> > > > > > > > > > > >
> > > > > > > > > > > > Jun
> > > > > > > > > > > >
> > > > > > > > > > > > On Fri, Feb 24, 2017 at 8:10 AM, Jay Kreps <
> > > > j...@confluent.io
> > > > > >
> > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > >> A couple of quick points:
> > > > > > > > > > > >>
> > > > > > > > > > > >> 1. Even though the implementation of this quota is
> > only
> > > > > using
> > > > > > io
> > > > > > > > > > thread
> > > > > > > > > > > >> time, i think we should call it something like
> > > > > "request-time".
> > > > > > > > This
> > > > > > > > > > will
> > > > > > > > > > > >> give us flexibility to improve the implementation to
> > > cover
> > > > > > > network
> > > > > > > > > > > threads
> > > > > > > > > > > >> in the future and will avoid exposing internal
> details
> > > > like
> > > > > > our
> > > > > > > > > thread
> > > > > > > > > > > >> pools on the server.
> > > > > > > > > > > >>
> > > > > > > > > > > >> 2. Jun/Roger, I get what you are trying to fix but
> the
> > > > idea
> > > > > of
> > > > > > > > > > > >> thread/units
> > > > > > > > > > > >> is super unintuitive as a user-facing knob. I had to
> > > read
> > > > > the
> > > > > > > KIP
> > > > > > > > > like
> > > > > > > > > > > >> eight times to understand this. I'm not sure that
> your
> > > > point
> > > > > > > that
> > > > > > > > > > > >> increasing the number of threads is a problem with a
> > > > > > > > > percentage-based
> > > > > > > > > > > >> value, it really depends on whether the user thinks
> > > about
> > > > > the
> > > > > > > > > > > "percentage
> > > > > > > > > > > >> of request processing time" or "thread units". If
> they
> > > > think
> > > > > > "I
> > > > > > > > have
> > > > > > > > > > > >> allocated 10% of my request processing time to user
> x"
> > > > then
> > > > > it
> > > > > > > is
> > > > > > > > a
> > > > > > > > > > bug
> > > > > > > > > > > >> that increasing the thread count decreases that
> > percent
> > > as
> > > > > it
> > > > > > > does
> > > > > > > > > in
> > > > > > > > > > > the
> > > > > > > > > > > >> current proposal. As a practical matter I think the
> > only
> > > > way
> > > > > > to
> > > > > > > > > > actually
> > > > > > > > > > > >> reason about this is as a percent---I just don't
> > believe
> > > > > > people
> > > > > > > > are
> > > > > > > > > > > going
> > > > > > > > > > > >> to think, "ah, 4.3 thread units, that is the right
> > > > amount!".
> > > > > > > > > Instead I
> > > > > > > > > > > >> think they have to understand this thread unit
> > concept,
> > > > > figure
> > > > > > > out
> > > > > > > > > > what
> > > > > > > > > > > >> they have set in number of threads, compute a
> percent
> > > and
> > > > > then
> > > > > > > > come
> > > > > > > > > up
> > > > > > > > > > > >> with
> > > > > > > > > > > >> the number of thread units, and these will all be
> > wrong
> > > if
> > > > > > that
> > > > > > > > > thread
> > > > > > > > > > > >> count changes. I also think this ties us to
> throttling
> > > the
> > > > > I/O
> > > > > > > > > thread
> > > > > > > > > > > >> pool,
> > > > > > > > > > > >> which may not be where we want to end up.
> > > > > > > > > > > >>
> > > > > > > > > > > >> 3. For what it's worth I do think having a single
> > > > > throttle_ms
> > > > > > > > field
> > > > > > > > > in
> > > > > > > > > > > all
> > > > > > > > > > > >> the responses that combines all throttling from all
> > > quotas
> > > > > is
> > > > > > > > > probably
> > > > > > > > > > > the
> > > > > > > > > > > >> simplest. There could be a use case for having
> > separate
> > > > > fields
> > > > > > > for
> > > > > > > > > > each,
> > > > > > > > > > > >> but I think that is actually harder to use/monitor
> in
> > > the
> > > > > > common
> > > > > > > > > case
> > > > > > > > > > so
> > > > > > > > > > > >> unless someone has a use case I think just one
> should
> > be
> > > > > fine.
> > > > > > > > > > > >>
> > > > > > > > > > > >> -Jay
> > > > > > > > > > > >>
> > > > > > > > > > > >> On Fri, Feb 24, 2017 at 4:21 AM, Rajini Sivaram <
> > > > > > > > > > > rajinisiva...@gmail.com>
> > > > > > > > > > > >> wrote:
> > > > > > > > > > > >>
> > > > > > > > > > > >> > I have updated the KIP based on the discussions so
> > > far.
> > > > > > > > > > > >> >
> > > > > > > > > > > >> >
> > > > > > > > > > > >> > Regards,
> > > > > > > > > > > >> >
> > > > > > > > > > > >> > Rajini
> > > > > > > > > > > >> >
> > > > > > > > > > > >> > On Thu, Feb 23, 2017 at 11:29 PM, Rajini Sivaram <
> > > > > > > > > > > >> rajinisiva...@gmail.com>
> > > > > > > > > > > >> > wrote:
> > > > > > > > > > > >> >
> > > > > > > > > > > >> > > Thank you all for the feedback.
> > > > > > > > > > > >> > >
> > > > > > > > > > > >> > > Ismael #1. It makes sense not to throttle
> > > inter-broker
> > > > > > > > requests
> > > > > > > > > > like
> > > > > > > > > > > >> > > LeaderAndIsr etc. The simplest way to ensure
> that
> > > > > clients
> > > > > > > > cannot
> > > > > > > > > > use
> > > > > > > > > > > >> > these
> > > > > > > > > > > >> > > requests to bypass quotas for DoS attacks is to
> > > ensure
> > > > > > that
> > > > > > > > ACLs
> > > > > > > > > > > >> prevent
> > > > > > > > > > > >> > > clients from using these requests and
> unauthorized
> > > > > > requests
> > > > > > > > are
> > > > > > > > > > > >> included
> > > > > > > > > > > >> > > towards quotas.
> > > > > > > > > > > >> > >
> > > > > > > > > > > >> > > Ismael #2, Jay #1 : I was thinking that these
> > quotas
> > > > can
> > > > > > > > return
> > > > > > > > > a
> > > > > > > > > > > >> > separate
> > > > > > > > > > > >> > > throttle time, and all utilization based quotas
> > > could
> > > > > use
> > > > > > > the
> > > > > > > > > same
> > > > > > > > > > > >> field
> > > > > > > > > > > >> > > (we won't add another one for network thread
> > > > utilization
> > > > > > for
> > > > > > > > > > > >> instance).
> > > > > > > > > > > >> > But
> > > > > > > > > > > >> > > perhaps it makes sense to keep byte rate quotas
> > > > separate
> > > > > > in
> > > > > > > > > > > >> produce/fetch
> > > > > > > > > > > >> > > responses to provide separate metrics? Agree
> with
> > > > Ismael
> > > > > > > that
> > > > > > > > > the
> > > > > > > > > > > >> name of
> > > > > > > > > > > >> > > the existing field should be changed if we have
> > two.
> > > > > Happy
> > > > > > > to
> > > > > > > > > > switch
> > > > > > > > > > > >> to a
> > > > > > > > > > > >> > > single combined throttle time if that is
> > sufficient.
> > > > > > > > > > > >> > >
> > > > > > > > > > > >> > > Ismael #4, #5, #6: Will update KIP. Will use dot
> > > > > separated
> > > > > > > > name
> > > > > > > > > > for
> > > > > > > > > > > >> new
> > > > > > > > > > > >> > > property. Replication quotas use dot separated,
> so
> > > it
> > > > > will
> > > > > > > be
> > > > > > > > > > > >> consistent
> > > > > > > > > > > >> > > with all properties except byte rate quotas.
> > > > > > > > > > > >> > >
> > > > > > > > > > > >> > > Radai: #1 Request processing time rather than
> > > request
> > > > > rate
> > > > > > > > were
> > > > > > > > > > > chosen
> > > > > > > > > > > >> > > because the time per request can vary
> > significantly
> > > > > > between
> > > > > > > > > > requests
> > > > > > > > > > > >> as
> > > > > > > > > > > >> > > mentioned in the discussion and KIP.
> > > > > > > > > > > >> > > #2 Two separate quotas for heartbeats/regular
> > > requests
> > > > > > feel
> > > > > > > > like
> > > > > > > > > > > more
> > > > > > > > > > > >> > > configuration and more metrics. Since most users
> > > would
> > > > > set
> > > > > > > > > quotas
> > > > > > > > > > > >> higher
> > > > > > > > > > > >> > > than the expected usage and quotas are more of a
> > > > safety
> > > > > > > net, a
> > > > > > > > > > > single
> > > > > > > > > > > >> > quota
> > > > > > > > > > > >> > > should work in most cases.
> > > > > > > > > > > >> > > #3 The number of requests in purgatory is
> limited
> > > by
> > > > > the
> > > > > > > > number
> > > > > > > > > > of
> > > > > > > > > > > >> > active
> > > > > > > > > > > >> > > connections since only one request per
> connection
> > > will
> > > > > be
> > > > > > > > > > throttled
> > > > > > > > > > > >> at a
> > > > > > > > > > > >> > > time.
> > > > > > > > > > > >> > > #4 As with byte rate quotas, to use the full
> > > allocated
> > > > > > > quotas,
> > > > > > > > > > > >> > > clients/users would need to use partitions that
> > are
> > > > > > > > distributed
> > > > > > > > > > > across
> > > > > > > > > > > >> > the
> > > > > > > > > > > >> > > cluster. The alternative of using cluster-wide
> > > quotas
> > > > > > > instead
> > > > > > > > of
> > > > > > > > > > > >> > per-broker
> > > > > > > > > > > >> > > quotas would be far too complex to implement.
> > > > > > > > > > > >> > >
> > > > > > > > > > > >> > > Dong : We currently have two ClientQuotaManagers
> > for
> > > > > quota
> > > > > > > > types
> > > > > > > > > > > Fetch
> > > > > > > > > > > >> > and
> > > > > > > > > > > >> > > Produce. A new one will be added for IOThread,
> > which
> > > > > > manages
> > > > > > > > > > quotas
> > > > > > > > > > > >> for
> > > > > > > > > > > >> > I/O
> > > > > > > > > > > >> > > thread utilization. This will not update the
> Fetch
> > > or
> > > > > > > Produce
> > > > > > > > > > > >> queue-size,
> > > > > > > > > > > >> > > but will have a separate metric for the
> > > queue-size. I
> > > > > > > wasn't
> > > > > > > > > > > >> planning to
> > > > > > > > > > > >> > > add any additional metrics apart from the
> > equivalent
> > > > > ones
> > > > > > > for
> > > > > > > > > > > existing
> > > > > > > > > > > >> > > quotas as part of this KIP. Ratio of byte-rate
> to
> > > I/O
> > > > > > thread
> > > > > > > > > > > >> utilization
> > > > > > > > > > > >> > > could be slightly misleading since it depends on
> > the
> > > > > > > sequence
> > > > > > > > of
> > > > > > > > > > > >> > requests.
> > > > > > > > > > > >> > > But we can look into more metrics after the KIP
> is
> > > > > > > implemented
> > > > > > > > > if
> > > > > > > > > > > >> > required.
> > > > > > > > > > > >> > >
> > > > > > > > > > > >> > > I think we need to limit the maximum delay since
> > all
> > > > > > > requests
> > > > > > > > > are
> > > > > > > > > > > >> > > throttled. If a client has a quota of 0.001
> units
> > > and
> > > > a
> > > > > > > single
> > > > > > > > > > > request
> > > > > > > > > > > >> > used
> > > > > > > > > > > >> > > 50ms, we don't want to delay all requests from
> the
> > > > > client
> > > > > > by
> > > > > > > > 50
> > > > > > > > > > > >> seconds,
> > > > > > > > > > > >> > > throwing the client out of all its consumer
> > groups.
> > > > The
> > > > > > > issue
> > > > > > > > is
> > > > > > > > > > > only
> > > > > > > > > > > >> if
> > > > > > > > > > > >> > a
> > > > > > > > > > > >> > > user is allocated a quota that is insufficient
> to
> > > > > process
> > > > > > > one
> > > > > > > > > > large
> > > > > > > > > > > >> > > request. The expectation is that the units
> > allocated
> > > > per
> > > > > > > user
> > > > > > > > > will
> > > > > > > > > > > be
> > > > > > > > > > > >> > much
> > > > > > > > > > > >> > > higher than the time taken to process one
> request
> > > and
> > > > > the
> > > > > > > > limit
> > > > > > > > > > > should
> > > > > > > > > > > >> > > seldom be applied. Agree this needs proper
> > > > > documentation.
> > > > > > > > > > > >> > >
> > > > > > > > > > > >> > > Regards,
> > > > > > > > > > > >> > >
> > > > > > > > > > > >> > > Rajini
> > > > > > > > > > > >> > >
> > > > > > > > > > > >> > >
> > > > > > > > > > > >> > > On Thu, Feb 23, 2017 at 8:04 PM, radai <
> > > > > > > > > > radai.rosenbl...@gmail.com>
> > > > > > > > > > > >> > wrote:
> > > > > > > > > > > >> > >
> > > > > > > > > > > >> > >> @jun: i wasnt concerned about tying up a
> request
> > > > > > processing
> > > > > > > > > > thread,
> > > > > > > > > > > >> but
> > > > > > > > > > > >> > >> IIUC the code does still read the entire
> request
> > > out,
> > > > > > which
> > > > > > > > > might
> > > > > > > > > > > >> add-up
> > > > > > > > > > > >> > >> to
> > > > > > > > > > > >> > >> a non-negligible amount of memory.
> > > > > > > > > > > >> > >>
> > > > > > > > > > > >> > >> On Thu, Feb 23, 2017 at 11:55 AM, Dong Lin <
> > > > > > > > > lindon...@gmail.com>
> > > > > > > > > > > >> wrote:
> > > > > > > > > > > >> > >>
> > > > > > > > > > > >> > >> > Hey Rajini,
> > > > > > > > > > > >> > >> >
> > > > > > > > > > > >> > >> > The current KIP says that the maximum delay
> > will
> > > be
> > > > > > > reduced
> > > > > > > > > to
> > > > > > > > > > > >> window
> > > > > > > > > > > >> > >> size
> > > > > > > > > > > >> > >> > if it is larger than the window size. I have
> a
> > > > > concern
> > > > > > > with
> > > > > > > > > > this:
> > > > > > > > > > > >> > >> >
> > > > > > > > > > > >> > >> > 1) This essentially means that the user is
> > > allowed
> > > > to
> > > > > > > > exceed
> > > > > > > > > > > their
> > > > > > > > > > > >> > quota
> > > > > > > > > > > >> > >> > over a long period of time. Can you provide
> an
> > > > upper
> > > > > > > bound
> > > > > > > > on
> > > > > > > > > > > this
> > > > > > > > > > > >> > >> > deviation?
> > > > > > > > > > > >> > >> >
> > > > > > > > > > > >> > >> > 2) What is the motivation for cap the maximum
> > > delay
> > > > > by
> > > > > > > the
> > > > > > > > > > window
> > > > > > > > > > > >> > size?
> > > > > > > > > > > >> > >> I
> > > > > > > > > > > >> > >> > am wondering if there is better alternative
> to
> > > > > address
> > > > > > > the
> > > > > > > > > > > problem.
> > > > > > > > > > > >> > >> >
> > > > > > > > > > > >> > >> > 3) It means that the existing metric-related
> > > config
> > > > > > will
> > > > > > > > > have a
> > > > > > > > > > > >> more
> > > > > > > > > > > >> > >> > directly impact on the mechanism of this
> > > > > > > > io-thread-unit-based
> > > > > > > > > > > >> quota.
> > > > > > > > > > > >> > The
> > > > > > > > > > > >> > >> > may be an important change depending on the
> > > answer
> > > > to
> > > > > > 1)
> > > > > > > > > above.
> > > > > > > > > > > We
> > > > > > > > > > > >> > >> probably
> > > > > > > > > > > >> > >> > need to document this more explicitly.
> > > > > > > > > > > >> > >> >
> > > > > > > > > > > >> > >> > Dong
> > > > > > > > > > > >> > >> >
> > > > > > > > > > > >> > >> >
> > > > > > > > > > > >> > >> > On Thu, Feb 23, 2017 at 10:56 AM, Dong Lin <
> > > > > > > > > > lindon...@gmail.com>
> > > > > > > > > > > >> > wrote:
> > > > > > > > > > > >> > >> >
> > > > > > > > > > > >> > >> > > Hey Jun,
> > > > > > > > > > > >> > >> > >
> > > > > > > > > > > >> > >> > > Yeah you are right. I thought it wasn't
> > because
> > > > at
> > > > > > > > LinkedIn
> > > > > > > > > > it
> > > > > > > > > > > >> will
> > > > > > > > > > > >> > be
> > > > > > > > > > > >> > >> > too
> > > > > > > > > > > >> > >> > > much pressure on inGraph to expose those
> > > > > per-clientId
> > > > > > > > > metrics
> > > > > > > > > > > so
> > > > > > > > > > > >> we
> > > > > > > > > > > >> > >> ended
> > > > > > > > > > > >> > >> > > up printing them periodically to local log.
> > > Never
> > > > > > mind
> > > > > > > if
> > > > > > > > > it
> > > > > > > > > > is
> > > > > > > > > > > >> not
> > > > > > > > > > > >> > a
> > > > > > > > > > > >> > >> > > general problem.
> > > > > > > > > > > >> > >> > >
> > > > > > > > > > > >> > >> > > Hey Rajini,
> > > > > > > > > > > >> > >> > >
> > > > > > > > > > > >> > >> > > - I agree with Jay that we probably don't
> > want
> > > to
> > > > > > add a
> > > > > > > > new
> > > > > > > > > > > field
> > > > > > > > > > > >> > for
> > > > > > > > > > > >> > >> > > every quota ProduceResponse or
> FetchResponse.
> > > Is
> > > > > > there
> > > > > > > > any
> > > > > > > > > > > >> use-case
> > > > > > > > > > > >> > >> for
> > > > > > > > > > > >> > >> > > having separate throttle-time fields for
> > > > > > > byte-rate-quota
> > > > > > > > > and
> > > > > > > > > > > >> > >> > > io-thread-unit-quota? You probably need to
> > > > document
> > > > > > > this
> > > > > > > > as
> > > > > > > > > > > >> > interface
> > > > > > > > > > > >> > >> > > change if you plan to add new field in any
> > > > request.
> > > > > > > > > > > >> > >> > >
> > > > > > > > > > > >> > >> > > - I don't think IOThread belongs to
> > quotaType.
> > > > The
> > > > > > > > existing
> > > > > > > > > > > quota
> > > > > > > > > > > >> > >> types
> > > > > > > > > > > >> > >> > > (i.e. Produce/Fetch/LeaderReplicatio
> > > > > > > > n/FollowerReplication)
> > > > > > > > > > > >> identify
> > > > > > > > > > > >> > >> the
> > > > > > > > > > > >> > >> > > type of request that are throttled, not the
> > > quota
> > > > > > > > mechanism
> > > > > > > > > > > that
> > > > > > > > > > > >> is
> > > > > > > > > > > >> > >> > applied.
> > > > > > > > > > > >> > >> > >
> > > > > > > > > > > >> > >> > > - If a request is throttled due to this
> > > > > > > > > io-thread-unit-based
> > > > > > > > > > > >> quota,
> > > > > > > > > > > >> > is
> > > > > > > > > > > >> > >> > the
> > > > > > > > > > > >> > >> > > existing queue-size metric in
> > > ClientQuotaManager
> > > > > > > > > incremented?
> > > > > > > > > > > >> > >> > >
> > > > > > > > > > > >> > >> > > - In the interest of providing guide line
> for
> > > > admin
> > > > > > to
> > > > > > > > > decide
> > > > > > > > > > > >> > >> > > io-thread-unit-based quota and for user to
> > > > > understand
> > > > > > > its
> > > > > > > > > > > impact
> > > > > > > > > > > >> on
> > > > > > > > > > > >> > >> their
> > > > > > > > > > > >> > >> > > traffic, would it be useful to have a
> metric
> > > that
> > > > > > shows
> > > > > > > > the
> > > > > > > > > > > >> overall
> > > > > > > > > > > >> > >> > > byte-rate per io-thread-unit? Can we also
> > show
> > > > > this a
> > > > > > > > > > > >> per-clientId
> > > > > > > > > > > >> > >> > metric?
> > > > > > > > > > > >> > >> > >
> > > > > > > > > > > >> > >> > > Thanks,
> > > > > > > > > > > >> > >> > > Dong
> > > > > > > > > > > >> > >> > >
> > > > > > > > > > > >> > >> > >
> > > > > > > > > > > >> > >> > > On Thu, Feb 23, 2017 at 9:25 AM, Jun Rao <
> > > > > > > > j...@confluent.io
> > > > > > > > > >
> > > > > > > > > > > >> wrote:
> > > > > > > > > > > >> > >> > >
> > > > > > > > > > > >> > >> > >> Hi, Ismael,
> > > > > > > > > > > >> > >> > >>
> > > > > > > > > > > >> > >> > >> For #3, typically, an admin won't
> configure
> > > more
> > > > > io
> > > > > > > > > threads
> > > > > > > > > > > than
> > > > > > > > > > > >> > CPU
> > > > > > > > > > > >> > >> > >> cores,
> > > > > > > > > > > >> > >> > >> but it's possible for an admin to start
> with
> > > > fewer
> > > > > > io
> > > > > > > > > > threads
> > > > > > > > > > > >> than
> > > > > > > > > > > >> > >> cores
> > > > > > > > > > > >> > >> > >> and grow that later on.
> > > > > > > > > > > >> > >> > >>
> > > > > > > > > > > >> > >> > >> Hi, Dong,
> > > > > > > > > > > >> > >> > >>
> > > > > > > > > > > >> > >> > >> I think the throttleTime sensor on the
> > broker
> > > > > tells
> > > > > > > the
> > > > > > > > > > admin
> > > > > > > > > > > >> > >> whether a
> > > > > > > > > > > >> > >> > >> user/clentId is throttled or not.
> > > > > > > > > > > >> > >> > >>
> > > > > > > > > > > >> > >> > >> Hi, Radi,
> > > > > > > > > > > >> > >> > >>
> > > > > > > > > > > >> > >> > >> The reasoning for delaying the throttled
> > > > requests
> > > > > on
> > > > > > > the
> > > > > > > > > > > broker
> > > > > > > > > > > >> > >> instead
> > > > > > > > > > > >> > >> > of
> > > > > > > > > > > >> > >> > >> returning an error immediately is that the
> > > > latter
> > > > > > has
> > > > > > > no
> > > > > > > > > way
> > > > > > > > > > > to
> > > > > > > > > > > >> > >> prevent
> > > > > > > > > > > >> > >> > >> the
> > > > > > > > > > > >> > >> > >> client from retrying immediately, which
> will
> > > > make
> > > > > > > things
> > > > > > > > > > > worse.
> > > > > > > > > > > >> The
> > > > > > > > > > > >> > >> > >> delaying logic is based off a delay
> queue. A
> > > > > > separate
> > > > > > > > > > > expiration
> > > > > > > > > > > >> > >> thread
> > > > > > > > > > > >> > >> > >> just waits on the next to be expired
> > request.
> > > > So,
> > > > > it
> > > > > > > > > doesn't
> > > > > > > > > > > tie
> > > > > > > > > > > >> > up a
> > > > > > > > > > > >> > >> > >> request handler thread.
> > > > > > > > > > > >> > >> > >>
> > > > > > > > > > > >> > >> > >> Thanks,
> > > > > > > > > > > >> > >> > >>
> > > > > > > > > > > >> > >> > >> Jun
> > > > > > > > > > > >> > >> > >>
> > > > > > > > > > > >> > >> > >> On Thu, Feb 23, 2017 at 9:07 AM, Ismael
> > Juma <
> > > > > > > > > > > ism...@juma.me.uk
> > > > > > > > > > > >> >
> > > > > > > > > > > >> > >> wrote:
> > > > > > > > > > > >> > >> > >>
> > > > > > > > > > > >> > >> > >> > Hi Jay,
> > > > > > > > > > > >> > >> > >> >
> > > > > > > > > > > >> > >> > >> > Regarding 1, I definitely like the
> > > simplicity
> > > > of
> > > > > > > > > keeping a
> > > > > > > > > > > >> single
> > > > > > > > > > > >> > >> > >> throttle
> > > > > > > > > > > >> > >> > >> > time field in the response. The downside
> > is
> > > > that
> > > > > > the
> > > > > > > > > > client
> > > > > > > > > > > >> > metrics
> > > > > > > > > > > >> > >> > >> will be
> > > > > > > > > > > >> > >> > >> > more coarse grained.
> > > > > > > > > > > >> > >> > >> >
> > > > > > > > > > > >> > >> > >> > Regarding 3, we have
> > > > > `leader.imbalance.per.broker.
> > > > > > > > > > > percentage`
> > > > > > > > > > > >> > and
> > > > > > > > > > > >> > >> > >> > `log.cleaner.min.cleanable.ratio`.
> > > > > > > > > > > >> > >> > >> >
> > > > > > > > > > > >> > >> > >> > Ismael
> > > > > > > > > > > >> > >> > >> >
> > > > > > > > > > > >> > >> > >> > On Thu, Feb 23, 2017 at 4:43 PM, Jay
> > Kreps <
> > > > > > > > > > > j...@confluent.io>
> > > > > > > > > > > >> > >> wrote:
> > > > > > > > > > > >> > >> > >> >
> > > > > > > > > > > >> > >> > >> > > A few minor comments:
> > > > > > > > > > > >> > >> > >> > >
> > > > > > > > > > > >> > >> > >> > > 1. Isn't it the case that the
> > > throttling
> > > > > time
> > > > > > > > > > response
> > > > > > > > > > > >> field
> > > > > > > > > > > >> > >> > should
> > > > > > > > > > > >> > >> > >> > have
> > > > > > > > > > > >> > >> > >> > > the total time your request was
> > > throttled
> > > > > > > > > > irrespective
> > > > > > > > > > > of
> > > > > > > > > > > >> > the
> > > > > > > > > > > >> > >> > >> quotas
> > > > > > > > > > > >> > >> > >> > > that
> > > > > > > > > > > >> > >> > >> > > caused that. Limiting it to byte
> rate
> > > > quota
> > > > > > > > doesn't
> > > > > > > > > > > make
> > > > > > > > > > > >> > >> sense,
> > > > > > > > > > > >> > >> > >> but I
> > > > > > > > > > > >> > >> > >> > > also
> > > > > > > > > > > >> > >> > >> > > I don't think we want to end up
> > adding
> > > > new
> > > > > > > fields
> > > > > > > > > in
> > > > > > > > > > > the
> > > > > > > > > > > >> > >> response
> > > > > > > > > > > >> > >> > >> for
> > > > > > > > > > > >> > >> > >> > > every
> > > > > > > > > > > >> > >> > >> > > single thing we quota, right?
> > > > > > > > > > > >> > >> > >> > > 2. I don't think we should make
> this
> > > > quota
> > > > > > > > > > specifically
> > > > > > > > > > > >> > about
> > > > > > > > > > > >> > >> io
> > > > > > > > > > > >> > >> > >> > > threads. Once we introduce these
> > quotas
> > > > > > people
> > > > > > > > set
> > > > > > > > > > them
> > > > > > > > > > > >> and
> > > > > > > > > > > >> > >> > expect
> > > > > > > > > > > >> > >> > >> > them
> > > > > > > > > > > >> > >> > >> > > to
> > > > > > > > > > > >> > >> > >> > > be enforced (and if they aren't it
> > may
> > > > > cause
> > > > > > an
> > > > > > > > > > > outage).
> > > > > > > > > > > >> As
> > > > > > > > > > > >> > a
> > > > > > > > > > > >> > >> > >> result
> > > > > > > > > > > >> > >> > >> > > they
> > > > > > > > > > > >> > >> > >> > > are a bit more sensitive than
> normal
> > > > > > configs, I
> > > > > > > > > > think.
> > > > > > > > > > > >> The
> > > > > > > > > > > >> > >> > current
> > > > > > > > > > > >> > >> > >> > > thread
> > > > > > > > > > > >> > >> > >> > > pools seem like something of an
> > > > > > implementation
> > > > > > > > > detail
> > > > > > > > > > > and
> > > > > > > > > > > >> > not
> > > > > > > > > > > >> > >> the
> > > > > > > > > > > >> > >> > >> > level
> > > > > > > > > > > >> > >> > >> > > the
> > > > > > > > > > > >> > >> > >> > > user-facing quotas should be
> involved
> > > > > with. I
> > > > > > > > think
> > > > > > > > > > it
> > > > > > > > > > > >> might
> > > > > > > > > > > >> > >> be
> > > > > > > > > > > >> > >> > >> better
> > > > > > > > > > > >> > >> > >> > > to
> > > > > > > > > > > >> > >> > >> > > make this a general request-time
> > > throttle
> > > > > > with
> > > > > > > no
> > > > > > > > > > > >> mention in
> > > > > > > > > > > >> > >> the
> > > > > > > > > > > >> > >> > >> > naming
> > > > > > > > > > > >> > >> > >> > > about I/O threads and simply
> > > acknowledge
> > > > > the
> > > > > > > > > current
> > > > > > > > > > > >> > >> limitation
> > > > > > > > > > > >> > >> > >> (which
> > > > > > > > > > > >> > >> > >> > > we
> > > > > > > > > > > >> > >> > >> > > may someday fix) in the docs that
> > this
> > > > > covers
> > > > > > > > only
> > > > > > > > > > the
> > > > > > > > > > > >> time
> > > > > > > > > > > >> > >> after
> > > > > > > > > > > >> > >> > >> the
> > > > > > > > > > > >> > >> > >> > > thread is read off the network.
> > > > > > > > > > > >> > >> > >> > > 3. As such I think the right
> > interface
> > > to
> > > > > the
> > > > > > > > user
> > > > > > > > > > > would
> > > > > > > > > > > >> be
> > > > > > > > > > > >> > >> > >> something
> > > > > > > > > > > >> > >> > >> > > like percent_request_time and be in
> > > > > > {0,...100}
> > > > > > > or
> > > > > > > > > > > >> > >> > >> request_time_ratio
> > > > > > > > > > > >> > >> > >> > > and be
> > > > > > > > > > > >> > >> > >> > > in {0.0,...,1.0} (I think "ratio"
> is
> > > the
> > > > > > > > > terminology
> > > > > > > > > > we
> > > > > > > > > > > >> used
> > > > > > > > > > > >> > >> if
> > > > > > > > > > > >> > >> > the
> > > > > > > > > > > >> > >> > >> > > scale
> > > > > > > > > > > >> > >> > >> > > is between 0 and 1 in the other
> > > metrics,
> > > > > > > right?)
> > > > > > > > > > > >> > >> > >> > >
> > > > > > > > > > > >> > >> > >> > > -Jay
> > > > > > > > > > > >> > >> > >> > >
> > > > > > > > > > > >> > >> > >> > > On Thu, Feb 23, 2017 at 3:45 AM,
> Rajini
> > > > > Sivaram
> > > > > > <
> > > > > > > > > > > >> > >> > >> rajinisiva...@gmail.com
> > > > > > > > > > > >> > >> > >> > >
> > > > > > > > > > > >> > >> > >> > > wrote:
> > > > > > > > > > > >> > >> > >> > >
> > > > > > > > > > > >> > >> > >> > > > Guozhang/Dong,
> > > > > > > > > > > >> > >> > >> > > >
> > > > > > > > > > > >> > >> > >> > > > Thank you for the feedback.
> > > > > > > > > > > >> > >> > >> > > >
> > > > > > > > > > > >> > >> > >> > > > Guozhang : I have updated the
> section
> > on
> > > > > > > > > co-existence
> > > > > > > > > > of
> > > > > > > > > > > >> byte
> > > > > > > > > > > >> > >> rate
> > > > > > > > > > > >> > >> > >> and
> > > > > > > > > > > >> > >> > >> > > > request time quotas.
> > > > > > > > > > > >> > >> > >> > > >
> > > > > > > > > > > >> > >> > >> > > > Dong: I hadn't added much detail to
> > the
> > > > > > metrics
> > > > > > > > and
> > > > > > > > > > > >> sensors
> > > > > > > > > > > >> > >> since
> > > > > > > > > > > >> > >> > >> they
> > > > > > > > > > > >> > >> > >> > > are
> > > > > > > > > > > >> > >> > >> > > > going to be very similar to the
> > existing
> > > > > > metrics
> > > > > > > > and
> > > > > > > > > > > >> sensors.
> > > > > > > > > > > >> > >> To
> > > > > > > > > > > >> > >> > >> avoid
> > > > > > > > > > > >> > >> > >> > > > confusion, I have now added more
> > detail.
> > > > All
> > > > > > > > metrics
> > > > > > > > > > are
> > > > > > > > > > > >> in
> > > > > > > > > > > >> > the
> > > > > > > > > > > >> > >> > >> group
> > > > > > > > > > > >> > >> > >> > > > "quotaType" and all sensors have
> names
> > > > > > starting
> > > > > > > > with
> > > > > > > > > > > >> > >> "quotaType"
> > > > > > > > > > > >> > >> > >> (where
> > > > > > > > > > > >> > >> > >> > > > quotaType is Produce/Fetch/
> > > > > LeaderReplication/
> > > > > > > > > > > >> > >> > >> > > > FollowerReplication/*IOThread*).
> > > > > > > > > > > >> > >> > >> > > > So there will be no reuse of
> existing
> > > > > > > > > metrics/sensors.
> > > > > > > > > > > The
> > > > > > > > > > > >> > new
> > > > > > > > > > > >> > >> > ones
> > > > > > > > > > > >> > >> > >> for
> > > > > > > > > > > >> > >> > >> > > > request processing time based
> > throttling
> > > > > will
> > > > > > be
> > > > > > > > > > > >> completely
> > > > > > > > > > > >> > >> > >> independent
> > > > > > > > > > > >> > >> > >> > > of
> > > > > > > > > > > >> > >> > >> > > > existing metrics/sensors, but will
> be
> > > > > > consistent
> > > > > > > > in
> > > > > > > > > > > >> format.
> > > > > > > > > > > >> > >> > >> > > >
> > > > > > > > > > > >> > >> > >> > > > The existing throttle_time_ms field
> in
> > > > > > > > produce/fetch
> > > > > > > > > > > >> > responses
> > > > > > > > > > > >> > >> > will
> > > > > > > > > > > >> > >> > >> not
> > > > > > > > > > > >> > >> > >> > > be
> > > > > > > > > > > >> > >> > >> > > > impacted by this KIP. That will
> > continue
> > > > to
> > > > > > > return
> > > > > > > > > > > >> byte-rate
> > > > > > > > > > > >> > >> based
> > > > > > > > > > > >> > >> > >> > > > throttling times. In addition, a new
> > > field
> > > > > > > > > > > >> > >> > request_throttle_time_ms
> > > > > > > > > > > >> > >> > >> > will
> > > > > > > > > > > >> > >> > >> > > be
> > > > > > > > > > > >> > >> > >> > > > added to return request quota based
> > > > > throttling
> > > > > > > > > times.
> > > > > > > > > > > >> These
> > > > > > > > > > > >> > >> will
> > > > > > > > > > > >> > >> > be
> > > > > > > > > > > >> > >> > >> > > exposed
> > > > > > > > > > > >> > >> > >> > > > as new metrics on the client-side.
> > > > > > > > > > > >> > >> > >> > > >
> > > > > > > > > > > >> > >> > >> > > > Since all metrics and sensors are
> > > > different
> > > > > > for
> > > > > > > > each
> > > > > > > > > > > type
> > > > > > > > > > > >> of
> > > > > > > > > > > >> > >> > quota,
> > > > > > > > > > > >> > >> > >> I
> > > > > > > > > > > >> > >> > >> > > > believe there is already sufficient
> > > > metrics
> > > > > to
> > > > > > > > > monitor
> > > > > > > > > > > >> > >> throttling
> > > > > > > > > > > >> > >> > on
> > > > > > > > > > > >> > >> > >> > both
> > > > > > > > > > > >> > >> > >> > > > client and broker side for each type
> > of
> > > > > > > > throttling.
> > > > > > > > > > > >> > >> > >> > > >
> > > > > > > > > > > >> > >> > >> > > > Regards,
> > > > > > > > > > > >> > >> > >> > > >
> > > > > > > > > > > >> > >> > >> > > > Rajini
> > > > > > > > > > > >> > >> > >> > > >
> > > > > > > > > > > >> > >> > >> > > >
> > > > > > > > > > > >> > >> > >> > > > On Thu, Feb 23, 2017 at 4:32 AM,
> Dong
> > > Lin
> > > > <
> > > > > > > > > > > >> > lindon...@gmail.com
> > > > > > > > > > > >> > >> >
> > > > > > > > > > > >> > >> > >> wrote:
> > > > > > > > > > > >> > >> > >> > > >
> > > > > > > > > > > >> > >> > >> > > > > Hey Rajini,
> > > > > > > > > > > >> > >> > >> > > > >
> > > > > > > > > > > >> > >> > >> > > > > I think it makes a lot of sense to
> > use
> > > > > > > > > > io_thread_units
> > > > > > > > > > > >> as
> > > > > > > > > > > >> > >> metric
> > > > > > > > > > > >> > >> > >> to
> > > > > > > > > > > >> > >> > >> > > quota
> > > > > > > > > > > >> > >> > >> > > > > user's traffic here. LGTM
> overall. I
> > > > have
> > > > > > some
> > > > > > > > > > > questions
> > > > > > > > > > > >> > >> > regarding
> > > > > > > > > > > >> > >> > >> > > > sensors.
> > > > > > > > > > > >> > >> > >> > > > >
> > > > > > > > > > > >> > >> > >> > > > > - Can you be more specific in the
> > KIP
> > > > what
> > > > > > > > sensors
> > > > > > > > > > > will
> > > > > > > > > > > >> be
> > > > > > > > > > > >> > >> > added?
> > > > > > > > > > > >> > >> > >> For
> > > > > > > > > > > >> > >> > >> > > > > example, it will be useful to
> > specify
> > > > the
> > > > > > name
> > > > > > > > and
> > > > > > > > > > > >> > >> attributes of
> > > > > > > > > > > >> > >> > >> > these
> > > > > > > > > > > >> > >> > >> > > > new
> > > > > > > > > > > >> > >> > >> > > > > sensors.
> > > > > > > > > > > >> > >> > >> > > > >
> > > > > > > > > > > >> > >> > >> > > > > - We currently have throttle-time
> > and
> > > > > > > queue-size
> > > > > > > > > for
> > > > > > > > > > > >> > >> byte-rate
> > > > > > > > > > > >> > >> > >> based
> > > > > > > > > > > >> > >> > >> > > > quota.
> > > > > > > > > > > >> > >> > >> > > > > Are you going to have separate
> > > > > throttle-time
> > > > > > > and
> > > > > > > > > > > >> queue-size
> > > > > > > > > > > >> > >> for
> > > > > > > > > > > >> > >> > >> > > requests
> > > > > > > > > > > >> > >> > >> > > > > throttled by io_thread_unit-based
> > > quota,
> > > > > or
> > > > > > > will
> > > > > > > > > > they
> > > > > > > > > > > >> share
> > > > > > > > > > > >> > >> the
> > > > > > > > > > > >> > >> > >> same
> > > > > > > > > > > >> > >> > >> > > > > sensor?
> > > > > > > > > > > >> > >> > >> > > > >
> > > > > > > > > > > >> > >> > >> > > > > - Does the throttle-time in the
> > > > > > > ProduceResponse
> > > > > > > > > and
> > > > > > > > > > > >> > >> > FetchResponse
> > > > > > > > > > > >> > >> > >> > > > contains
> > > > > > > > > > > >> > >> > >> > > > > time due to io_thread_unit-based
> > > quota?
> > > > > > > > > > > >> > >> > >> > > > >
> > > > > > > > > > > >> > >> > >> > > > > - Currently kafka server doesn't
> not
> > > > > provide
> > > > > > > any
> > > > > > > > > log
> > > > > > > > > > > or
> > > > > > > > > > > >> > >> metrics
> > > > > > > > > > > >> > >> > >> that
> > > > > > > > > > > >> > >> > >> > > > tells
> > > > > > > > > > > >> > >> > >> > > > > whether any given clientId (or
> user)
> > > is
> > > > > > > > throttled.
> > > > > > > > > > > This
> > > > > > > > > > > >> is
> > > > > > > > > > > >> > >> not
> > > > > > > > > > > >> > >> > too
> > > > > > > > > > > >> > >> > >> > bad
> > > > > > > > > > > >> > >> > >> > > > > because we can still check the
> > > > client-side
> > > > > > > > > byte-rate
> > > > > > > > > > > >> metric
> > > > > > > > > > > >> > >> to
> > > > > > > > > > > >> > >> > >> > validate
> > > > > > > > > > > >> > >> > >> > > > > whether a given client is
> throttled.
> > > But
> > > > > > with
> > > > > > > > this
> > > > > > > > > > > >> > >> > io_thread_unit,
> > > > > > > > > > > >> > >> > >> > > there
> > > > > > > > > > > >> > >> > >> > > > > will be no way to validate
> whether a
> > > > given
> > > > > > > > client
> > > > > > > > > is
> > > > > > > > > > > >> slow
> > > > > > > > > > > >> > >> > because
> > > > > > > > > > > >> > >> > >> it
> > > > > > > > > > > >> > >> > >> > > has
> > > > > > > > > > > >> > >> > >> > > > > exceeded its io_thread_unit limit.
> > It
> > > is
> > > > > > > > necessary
> > > > > > > > > > for
> > > > > > > > > > > >> user
> > > > > > > > > > > >> > >> to
> > > > > > > > > > > >> > >> > be
> > > > > > > > > > > >> > >> > >> > able
> > > > > > > > > > > >> > >> > >> > > to
> > > > > > > > > > > >> > >> > >> > > > > know this information to figure
> how
> > > > > whether
> > > > > > > they
> > > > > > > > > > have
> > > > > > > > > > > >> > reached
> > > > > > > > > > > >> > >> > >> there
> > > > > > > > > > > >> > >> > >> > > quota
> > > > > > > > > > > >> > >> > >> > > > > limit. How about we add log4j log
> on
> > > the
> > > > > > > server
> > > > > > > > > side
> > > > > > > > > > > to
> > > > > > > > > > > >> > >> > >> periodically
> > > > > > > > > > > >> > >> > >> > > > print
> > > > > > > > > > > >> > >> > >> > > > > the (client_id,
> > > byte-rate-throttle-time,
> > > > > > > > > > > >> > >> > >> > io-thread-unit-throttle-time)
> > > > > > > > > > > >> > >> > >> > > so
> > > > > > > > > > > >> > >> > >> > > > > that kafka administrator can
> figure
> > > > those
> > > > > > > users
> > > > > > > > > that
> > > > > > > > > > > >> have
> > > > > > > > > > > >> > >> > reached
> > > > > > > > > > > >> > >> > >> > their
> > > > > > > > > > > >> > >> > >> > > > > limit and act accordingly?
> > > > > > > > > > > >> > >> > >> > > > >
> > > > > > > > > > > >> > >> > >> > > > > Thanks,
> > > > > > > > > > > >> > >> > >> > > > > Dong
> > > > > > > > > > > >> > >> > >> > > > >
> > > > > > > > > > > >> > >> > >> > > > >
> > > > > > > > > > > >> > >> > >> > > > >
> > > > > > > > > > > >> > >> > >> > > > >
> > > > > > > > > > > >> > >> > >> > > > >
> > > > > > > > > > > >> > >> > >> > > > > On Wed, Feb 22, 2017 at 4:46 PM,
> > > > Guozhang
> > > > > > > Wang <
> > > > > > > > > > > >> > >> > >> wangg...@gmail.com>
> > > > > > > > > > > >> > >> > >> > > > wrote:
> > > > > > > > > > > >> > >> > >> > > > >
> > > > > > > > > > > >> > >> > >> > > > > > Made a pass over the doc,
> overall
> > > LGTM
> > > > > > > except
> > > > > > > > a
> > > > > > > > > > > minor
> > > > > > > > > > > >> > >> comment
> > > > > > > > > > > >> > >> > on
> > > > > > > > > > > >> > >> > >> > the
> > > > > > > > > > > >> > >> > >> > > > > > throttling implementation:
> > > > > > > > > > > >> > >> > >> > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > Stated as "Request processing
> time
> > > > > > > throttling
> > > > > > > > > will
> > > > > > > > > > > be
> > > > > > > > > > > >> > >> applied
> > > > > > > > > > > >> > >> > on
> > > > > > > > > > > >> > >> > >> > top
> > > > > > > > > > > >> > >> > >> > > if
> > > > > > > > > > > >> > >> > >> > > > > > necessary." I thought that it
> > meant
> > > > the
> > > > > > > > request
> > > > > > > > > > > >> > processing
> > > > > > > > > > > >> > >> > time
> > > > > > > > > > > >> > >> > >> > > > > throttling
> > > > > > > > > > > >> > >> > >> > > > > > is applied first, but continue
> > > > reading I
> > > > > > > found
> > > > > > > > > it
> > > > > > > > > > > >> > actually
> > > > > > > > > > > >> > >> > >> meant to
> > > > > > > > > > > >> > >> > >> > > > apply
> > > > > > > > > > > >> > >> > >> > > > > > produce / fetch byte rate
> > throttling
> > > > > > first.
> > > > > > > > > > > >> > >> > >> > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > Also the last sentence "The
> > > remaining
> > > > > > delay
> > > > > > > if
> > > > > > > > > any
> > > > > > > > > > > is
> > > > > > > > > > > >> > >> applied
> > > > > > > > > > > >> > >> > to
> > > > > > > > > > > >> > >> > >> > the
> > > > > > > > > > > >> > >> > >> > > > > > response." is a bit confusing to
> > me.
> > > > > Maybe
> > > > > > > > > > rewording
> > > > > > > > > > > >> it a
> > > > > > > > > > > >> > >> bit?
> > > > > > > > > > > >> > >> > >> > > > > >
> > > > > > > > > > > >> > >> > >> > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > Guozhang
> > > > > > > > > > > >> > >> > >> > > > > >
> > > > > > > > > > > >> > >> > >> > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > On Wed, Feb 22, 2017 at 3:24 PM,
> > Jun
> > > > > Rao <
> > > > > > > > > > > >> > j...@confluent.io
> > > > > > > > > > > >> > >> >
> > > > > > > > > > > >> > >> > >> wrote:
> > > > > > > > > > > >> > >> > >> > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > Hi, Rajini,
> > > > > > > > > > > >> > >> > >> > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > Thanks for the updated KIP.
> The
> > > > latest
> > > > > > > > > proposal
> > > > > > > > > > > >> looks
> > > > > > > > > > > >> > >> good
> > > > > > > > > > > >> > >> > to
> > > > > > > > > > > >> > >> > >> me.
> > > > > > > > > > > >> > >> > >> > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > Jun
> > > > > > > > > > > >> > >> > >> > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > On Wed, Feb 22, 2017 at 2:19
> PM,
> > > > > Rajini
> > > > > > > > > Sivaram
> > > > > > > > > > <
> > > > > > > > > > > >> > >> > >> > > > > rajinisiva...@gmail.com
> > > > > > > > > > > >> > >> > >> > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > wrote:
> > > > > > > > > > > >> > >> > >> > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > Jun/Roger,
> > > > > > > > > > > >> > >> > >> > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > Thank you for the feedback.
> > > > > > > > > > > >> > >> > >> > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > 1. I have updated the KIP to
> > use
> > > > > > > absolute
> > > > > > > > > > units
> > > > > > > > > > > >> > >> instead of
> > > > > > > > > > > >> > >> > >> > > > > percentage.
> > > > > > > > > > > >> > >> > >> > > > > > > The
> > > > > > > > > > > >> > >> > >> > > > > > > > property is called*
> > > > io_thread_units*
> > > > > > to
> > > > > > > > > align
> > > > > > > > > > > with
> > > > > > > > > > > >> > the
> > > > > > > > > > > >> > >> > >> thread
> > > > > > > > > > > >> > >> > >> > > count
> > > > > > > > > > > >> > >> > >> > > > > > > > property *num.io.threads*.
> > When
> > > we
> > > > > > > > implement
> > > > > > > > > > > >> network
> > > > > > > > > > > >> > >> > thread
> > > > > > > > > > > >> > >> > >> > > > > utilization
> > > > > > > > > > > >> > >> > >> > > > > > > > quotas, we can add another
> > > > property
> > > > > > > > > > > >> > >> > *network_thread_units.*
> > > > > > > > > > > >> > >> > >> > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > 2. ControlledShutdown is
> > already
> > > > > > listed
> > > > > > > > > under
> > > > > > > > > > > the
> > > > > > > > > > > >> > >> exempt
> > > > > > > > > > > >> > >> > >> > > requests.
> > > > > > > > > > > >> > >> > >> > > > > Jun,
> > > > > > > > > > > >> > >> > >> > > > > > > did
> > > > > > > > > > > >> > >> > >> > > > > > > > you mean a different request
> > > that
> > > > > > needs
> > > > > > > to
> > > > > > > > > be
> > > > > > > > > > > >> added?
> > > > > > > > > > > >> > >> The
> > > > > > > > > > > >> > >> > >> four
> > > > > > > > > > > >> > >> > >> > > > > requests
> > > > > > > > > > > >> > >> > >> > > > > > > > currently exempt in the KIP
> > are
> > > > > > > > StopReplica,
> > > > > > > > > > > >> > >> > >> > ControlledShutdown,
> > > > > > > > > > > >> > >> > >> > > > > > > > LeaderAndIsr and
> > UpdateMetadata.
> > > > > These
> > > > > > > are
> > > > > > > > > > > >> controlled
> > > > > > > > > > > >> > >> > using
> > > > > > > > > > > >> > >> > >> > > > > > ClusterAction
> > > > > > > > > > > >> > >> > >> > > > > > > > ACL, so it is easy to
> exclude
> > > and
> > > > > only
> > > > > > > > > > throttle
> > > > > > > > > > > if
> > > > > > > > > > > >> > >> > >> > unauthorized.
> > > > > > > > > > > >> > >> > >> > > I
> > > > > > > > > > > >> > >> > >> > > > > > wasn't
> > > > > > > > > > > >> > >> > >> > > > > > > > sure if there are other
> > requests
> > > > > used
> > > > > > > only
> > > > > > > > > for
> > > > > > > > > > > >> > >> > inter-broker
> > > > > > > > > > > >> > >> > >> > that
> > > > > > > > > > > >> > >> > >> > > > > needed
> > > > > > > > > > > >> > >> > >> > > > > > > to
> > > > > > > > > > > >> > >> > >> > > > > > > > be excluded.
> > > > > > > > > > > >> > >> > >> > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > 3. I was thinking the
> smallest
> > > > > change
> > > > > > > > would
> > > > > > > > > be
> > > > > > > > > > > to
> > > > > > > > > > > >> > >> replace
> > > > > > > > > > > >> > >> > >> all
> > > > > > > > > > > >> > >> > >> > > > > > references
> > > > > > > > > > > >> > >> > >> > > > > > > to
> > > > > > > > > > > >> > >> > >> > > > > > > >
> *requestChannel.sendResponse()
> > *
> > > > > with
> > > > > > a
> > > > > > > > > local
> > > > > > > > > > > >> method
> > > > > > > > > > > >> > >> > >> > > > > > > >
> *sendResponseMaybeThrottle()*
> > > that
> > > > > > does
> > > > > > > > the
> > > > > > > > > > > >> > throttling
> > > > > > > > > > > >> > >> if
> > > > > > > > > > > >> > >> > >> any
> > > > > > > > > > > >> > >> > >> > > plus
> > > > > > > > > > > >> > >> > >> > > > > send
> > > > > > > > > > > >> > >> > >> > > > > > > > response. If we throttle
> first
> > > in
> > > > > > > > > > > >> > *KafkaApis.handle()*,
> > > > > > > > > > > >> > >> > the
> > > > > > > > > > > >> > >> > >> > time
> > > > > > > > > > > >> > >> > >> > > > > spent
> > > > > > > > > > > >> > >> > >> > > > > > > > within the method handling
> the
> > > > > request
> > > > > > > > will
> > > > > > > > > > not
> > > > > > > > > > > be
> > > > > > > > > > > >> > >> > recorded
> > > > > > > > > > > >> > >> > >> or
> > > > > > > > > > > >> > >> > >> > > used
> > > > > > > > > > > >> > >> > >> > > > > in
> > > > > > > > > > > >> > >> > >> > > > > > > > throttling. We can look into
> > > this
> > > > > > again
> > > > > > > > when
> > > > > > > > > > the
> > > > > > > > > > > >> PR
> > > > > > > > > > > >> > is
> > > > > > > > > > > >> > >> > ready
> > > > > > > > > > > >> > >> > >> > for
> > > > > > > > > > > >> > >> > >> > > > > > review.
> > > > > > > > > > > >> > >> > >> > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > Regards,
> > > > > > > > > > > >> > >> > >> > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > Rajini
> > > > > > > > > > > >> > >> > >> > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > On Wed, Feb 22, 2017 at 5:55
> > PM,
> > > > > Roger
> > > > > > > > > Hoover
> > > > > > > > > > <
> > > > > > > > > > > >> > >> > >> > > > > roger.hoo...@gmail.com>
> > > > > > > > > > > >> > >> > >> > > > > > > > wrote:
> > > > > > > > > > > >> > >> > >> > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > Great to see this KIP and
> > the
> > > > > > > excellent
> > > > > > > > > > > >> discussion.
> > > > > > > > > > > >> > >> > >> > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > To me, Jun's suggestion
> > makes
> > > > > sense.
> > > > > > > If
> > > > > > > > > my
> > > > > > > > > > > >> > >> application
> > > > > > > > > > > >> > >> > is
> > > > > > > > > > > >> > >> > >> > > > > allocated
> > > > > > > > > > > >> > >> > >> > > > > > 1
> > > > > > > > > > > >> > >> > >> > > > > > > > > request handler unit, then
> > > it's
> > > > as
> > > > > > if
> > > > > > > I
> > > > > > > > > > have a
> > > > > > > > > > > >> > Kafka
> > > > > > > > > > > >> > >> > >> broker
> > > > > > > > > > > >> > >> > >> > > with
> > > > > > > > > > > >> > >> > >> > > > a
> > > > > > > > > > > >> > >> > >> > > > > > > single
> > > > > > > > > > > >> > >> > >> > > > > > > > > request handler thread
> > > dedicated
> > > > > to
> > > > > > > me.
> > > > > > > > > > > That's
> > > > > > > > > > > >> the
> > > > > > > > > > > >> > >> > most I
> > > > > > > > > > > >> > >> > >> > can
> > > > > > > > > > > >> > >> > >> > > > use,
> > > > > > > > > > > >> > >> > >> > > > > > at
> > > > > > > > > > > >> > >> > >> > > > > > > > > least. That allocation
> > > doesn't
> > > > > > change
> > > > > > > > > even
> > > > > > > > > > if
> > > > > > > > > > > >> an
> > > > > > > > > > > >> > >> admin
> > > > > > > > > > > >> > >> > >> later
> > > > > > > > > > > >> > >> > >> > > > > > increases
> > > > > > > > > > > >> > >> > >> > > > > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > size of the request thread
> > > pool
> > > > on
> > > > > > the
> > > > > > > > > > broker.
> > > > > > > > > > > >> > It's
> > > > > > > > > > > >> > >> > >> similar
> > > > > > > > > > > >> > >> > >> > to
> > > > > > > > > > > >> > >> > >> > > > the
> > > > > > > > > > > >> > >> > >> > > > > > CPU
> > > > > > > > > > > >> > >> > >> > > > > > > > > abstraction that VMs and
> > > > > containers
> > > > > > > get
> > > > > > > > > from
> > > > > > > > > > > >> > >> hypervisors
> > > > > > > > > > > >> > >> > >> or
> > > > > > > > > > > >> > >> > >> > OS
> > > > > > > > > > > >> > >> > >> > > > > > > > schedulers.
> > > > > > > > > > > >> > >> > >> > > > > > > > > While different client
> > access
> > > > > > patterns
> > > > > > > > can
> > > > > > > > > > use
> > > > > > > > > > > >> > wildly
> > > > > > > > > > > >> > >> > >> > different
> > > > > > > > > > > >> > >> > >> > > > > > amounts
> > > > > > > > > > > >> > >> > >> > > > > > > > of
> > > > > > > > > > > >> > >> > >> > > > > > > > > request thread resources
> per
> > > > > > request,
> > > > > > > a
> > > > > > > > > > given
> > > > > > > > > > > >> > >> > application
> > > > > > > > > > > >> > >> > >> > will
> > > > > > > > > > > >> > >> > >> > > > > > > generally
> > > > > > > > > > > >> > >> > >> > > > > > > > > have a stable access
> pattern
> > > and
> > > > > can
> > > > > > > > > figure
> > > > > > > > > > > out
> > > > > > > > > > > >> > >> > >> empirically
> > > > > > > > > > > >> > >> > >> > how
> > > > > > > > > > > >> > >> > >> > > > > many
> > > > > > > > > > > >> > >> > >> > > > > > > > > "request thread units" it
> > > needs
> > > > to
> > > > > > > meet
> > > > > > > > > it's
> > > > > > > > > > > >> > >> > >> > throughput/latency
> > > > > > > > > > > >> > >> > >> > > > > > goals.
> > > > > > > > > > > >> > >> > >> > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > Cheers,
> > > > > > > > > > > >> > >> > >> > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > Roger
> > > > > > > > > > > >> > >> > >> > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > On Wed, Feb 22, 2017 at
> 8:53
> > > AM,
> > > > > Jun
> > > > > > > > Rao <
> > > > > > > > > > > >> > >> > >> j...@confluent.io>
> > > > > > > > > > > >> > >> > >> > > > wrote:
> > > > > > > > > > > >> > >> > >> > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > Hi, Rajini,
> > > > > > > > > > > >> > >> > >> > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > Thanks for the updated
> > KIP.
> > > A
> > > > > few
> > > > > > > more
> > > > > > > > > > > >> comments.
> > > > > > > > > > > >> > >> > >> > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > 1. A concern of
> > > > > > request_time_percent
> > > > > > > > is
> > > > > > > > > > that
> > > > > > > > > > > >> it's
> > > > > > > > > > > >> > >> not
> > > > > > > > > > > >> > >> > an
> > > > > > > > > > > >> > >> > >> > > > absolute
> > > > > > > > > > > >> > >> > >> > > > > > > > value.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > Let's say you give a
> user
> > a
> > > > 10%
> > > > > > > limit.
> > > > > > > > > If
> > > > > > > > > > > the
> > > > > > > > > > > >> > admin
> > > > > > > > > > > >> > >> > >> doubles
> > > > > > > > > > > >> > >> > >> > > the
> > > > > > > > > > > >> > >> > >> > > > > > > number
> > > > > > > > > > > >> > >> > >> > > > > > > > of
> > > > > > > > > > > >> > >> > >> > > > > > > > > > request handler threads,
> > > that
> > > > > user
> > > > > > > now
> > > > > > > > > > > >> actually
> > > > > > > > > > > >> > has
> > > > > > > > > > > >> > >> > >> twice
> > > > > > > > > > > >> > >> > >> > the
> > > > > > > > > > > >> > >> > >> > > > > > > absolute
> > > > > > > > > > > >> > >> > >> > > > > > > > > > capacity. This may
> confuse
> > > > > people
> > > > > > a
> > > > > > > > bit.
> > > > > > > > > > So,
> > > > > > > > > > > >> > >> perhaps
> > > > > > > > > > > >> > >> > >> > setting
> > > > > > > > > > > >> > >> > >> > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > quota
> > > > > > > > > > > >> > >> > >> > > > > > > > > > based on an absolute
> > request
> > > > > > thread
> > > > > > > > unit
> > > > > > > > > > is
> > > > > > > > > > > >> > better.
> > > > > > > > > > > >> > >> > >> > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > 2.
> > ControlledShutdownRequest
> > > > is
> > > > > > also
> > > > > > > > an
> > > > > > > > > > > >> > >> inter-broker
> > > > > > > > > > > >> > >> > >> > request
> > > > > > > > > > > >> > >> > >> > > > and
> > > > > > > > > > > >> > >> > >> > > > > > > needs
> > > > > > > > > > > >> > >> > >> > > > > > > > to
> > > > > > > > > > > >> > >> > >> > > > > > > > > > be excluded from
> > throttling.
> > > > > > > > > > > >> > >> > >> > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > 3. Implementation wise,
> I
> > am
> > > > > > > wondering
> > > > > > > > > if
> > > > > > > > > > > it's
> > > > > > > > > > > >> > >> simpler
> > > > > > > > > > > >> > >> > >> to
> > > > > > > > > > > >> > >> > >> > > apply
> > > > > > > > > > > >> > >> > >> > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > request
> > > > > > > > > > > >> > >> > >> > > > > > > > > > time throttling first in
> > > > > > > > > > KafkaApis.handle().
> > > > > > > > > > > >> > >> > Otherwise,
> > > > > > > > > > > >> > >> > >> we
> > > > > > > > > > > >> > >> > >> > > will
> > > > > > > > > > > >> > >> > >> > > > > > need
> > > > > > > > > > > >> > >> > >> > > > > > > to
> > > > > > > > > > > >> > >> > >> > > > > > > > > add
> > > > > > > > > > > >> > >> > >> > > > > > > > > > the throttling logic in
> > each
> > > > > type
> > > > > > of
> > > > > > > > > > > request.
> > > > > > > > > > > >> > >> > >> > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > Thanks,
> > > > > > > > > > > >> > >> > >> > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > Jun
> > > > > > > > > > > >> > >> > >> > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > On Wed, Feb 22, 2017 at
> > 5:58
> > > > AM,
> > > > > > > > Rajini
> > > > > > > > > > > >> Sivaram <
> > > > > > > > > > > >> > >> > >> > > > > > > > rajinisiva...@gmail.com
> > > > > > > > > > > >> > >> > >> > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > wrote:
> > > > > > > > > > > >> > >> > >> > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > Jun,
> > > > > > > > > > > >> > >> > >> > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > Thank you for the
> > review.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > I have reverted to the
> > > > > original
> > > > > > > KIP
> > > > > > > > > that
> > > > > > > > > > > >> > >> throttles
> > > > > > > > > > > >> > >> > >> based
> > > > > > > > > > > >> > >> > >> > on
> > > > > > > > > > > >> > >> > >> > > > > > request
> > > > > > > > > > > >> > >> > >> > > > > > > > > > handler
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > utilization. At the
> > > moment,
> > > > it
> > > > > > > uses
> > > > > > > > > > > >> percentage,
> > > > > > > > > > > >> > >> but
> > > > > > > > > > > >> > >> > I
> > > > > > > > > > > >> > >> > >> am
> > > > > > > > > > > >> > >> > >> > > > happy
> > > > > > > > > > > >> > >> > >> > > > > to
> > > > > > > > > > > >> > >> > >> > > > > > > > > change
> > > > > > > > > > > >> > >> > >> > > > > > > > > > to
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > a fraction (out of 1
> > > instead
> > > > > of
> > > > > > > 100)
> > > > > > > > > if
> > > > > > > > > > > >> > >> required. I
> > > > > > > > > > > >> > >> > >> have
> > > > > > > > > > > >> > >> > >> > > > added
> > > > > > > > > > > >> > >> > >> > > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > > examples
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > from this discussion
> to
> > > the
> > > > > KIP.
> > > > > > > > Also
> > > > > > > > > > > added
> > > > > > > > > > > >> a
> > > > > > > > > > > >> > >> > "Future
> > > > > > > > > > > >> > >> > >> > Work"
> > > > > > > > > > > >> > >> > >> > > > > > section
> > > > > > > > > > > >> > >> > >> > > > > > > > to
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > address network thread
> > > > > > > utilization.
> > > > > > > > > The
> > > > > > > > > > > >> > >> > configuration
> > > > > > > > > > > >> > >> > >> is
> > > > > > > > > > > >> > >> > >> > > > named
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > "request_time_percent"
> > > with
> > > > > the
> > > > > > > > > > > expectation
> > > > > > > > > > > >> > that
> > > > > > > > > > > >> > >> it
> > > > > > > > > > > >> > >> > >> can
> > > > > > > > > > > >> > >> > >> > > also
> > > > > > > > > > > >> > >> > >> > > > be
> > > > > > > > > > > >> > >> > >> > > > > > > used
> > > > > > > > > > > >> > >> > >> > > > > > > > as
> > > > > > > > > > > >> > >> > >> > > > > > > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > limit for network
> thread
> > > > > > > utilization
> > > > > > > > > > when
> > > > > > > > > > > >> that
> > > > > > > > > > > >> > is
> > > > > > > > > > > >> > >> > >> > > > implemented,
> > > > > > > > > > > >> > >> > >> > > > > so
> > > > > > > > > > > >> > >> > >> > > > > > > > that
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > users have to set only
> > one
> > > > > > config
> > > > > > > > for
> > > > > > > > > > the
> > > > > > > > > > > >> two
> > > > > > > > > > > >> > and
> > > > > > > > > > > >> > >> > not
> > > > > > > > > > > >> > >> > >> > have
> > > > > > > > > > > >> > >> > >> > > to
> > > > > > > > > > > >> > >> > >> > > > > > worry
> > > > > > > > > > > >> > >> > >> > > > > > > > > about
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > the internal
> > distribution
> > > of
> > > > > the
> > > > > > > > work
> > > > > > > > > > > >> between
> > > > > > > > > > > >> > the
> > > > > > > > > > > >> > >> > two
> > > > > > > > > > > >> > >> > >> > > thread
> > > > > > > > > > > >> > >> > >> > > > > > pools
> > > > > > > > > > > >> > >> > >> > > > > > > in
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > Kafka.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > Regards,
> > > > > > > > > > > >> > >> > >> > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > Rajini
> > > > > > > > > > > >> > >> > >> > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > On Wed, Feb 22, 2017
> at
> > > > 12:23
> > > > > > AM,
> > > > > > > > Jun
> > > > > > > > > > Rao
> > > > > > > > > > > <
> > > > > > > > > > > >> > >> > >> > > j...@confluent.io>
> > > > > > > > > > > >> > >> > >> > > > > > > wrote:
> > > > > > > > > > > >> > >> > >> > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > Hi, Rajini,
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > Thanks for the
> > proposal.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > The benefit of using
> > the
> > > > > > request
> > > > > > > > > > > >> processing
> > > > > > > > > > > >> > >> time
> > > > > > > > > > > >> > >> > >> over
> > > > > > > > > > > >> > >> > >> > the
> > > > > > > > > > > >> > >> > >> > > > > > request
> > > > > > > > > > > >> > >> > >> > > > > > > > > rate
> > > > > > > > > > > >> > >> > >> > > > > > > > > > is
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > exactly what people
> > have
> > > > > > said. I
> > > > > > > > > will
> > > > > > > > > > > just
> > > > > > > > > > > >> > >> expand
> > > > > > > > > > > >> > >> > >> that
> > > > > > > > > > > >> > >> > >> > a
> > > > > > > > > > > >> > >> > >> > > > bit.
> > > > > > > > > > > >> > >> > >> > > > > > > > > Consider
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > following case. The
> > > > producer
> > > > > > > > sends a
> > > > > > > > > > > >> produce
> > > > > > > > > > > >> > >> > request
> > > > > > > > > > > >> > >> > >> > > with a
> > > > > > > > > > > >> > >> > >> > > > > > 10MB
> > > > > > > > > > > >> > >> > >> > > > > > > > > > message
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > but compressed to
> > 100KB
> > > > with
> > > > > > > gzip.
> > > > > > > > > The
> > > > > > > > > > > >> > >> > >> decompression of
> > > > > > > > > > > >> > >> > >> > > the
> > > > > > > > > > > >> > >> > >> > > > > > > message
> > > > > > > > > > > >> > >> > >> > > > > > > > > on
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > broker could take
> > 10-15
> > > > > > seconds,
> > > > > > > > > > during
> > > > > > > > > > > >> which
> > > > > > > > > > > >> > >> > time,
> > > > > > > > > > > >> > >> > >> a
> > > > > > > > > > > >> > >> > >> > > > request
> > > > > > > > > > > >> > >> > >> > > > > > > > handler
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > thread is completely
> > > > > blocked.
> > > > > > In
> > > > > > > > > this
> > > > > > > > > > > >> case,
> > > > > > > > > > > >> > >> > neither
> > > > > > > > > > > >> > >> > >> the
> > > > > > > > > > > >> > >> > >> > > > > byte-in
> > > > > > > > > > > >> > >> > >> > > > > > > > quota
> > > > > > > > > > > >> > >> > >> > > > > > > > > > nor
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > the request rate
> quota
> > > may
> > > > > be
> > > > > > > > > > effective
> > > > > > > > > > > in
> > > > > > > > > > > >> > >> > >> protecting
> > > > > > > > > > > >> > >> > >> > the
> > > > > > > > > > > >> > >> > >> > > > > > broker.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > Consider
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > another case. A
> > consumer
> > > > > group
> > > > > > > > > starts
> > > > > > > > > > > >> with 10
> > > > > > > > > > > >> > >> > >> instances
> > > > > > > > > > > >> > >> > >> > > and
> > > > > > > > > > > >> > >> > >> > > > > > later
> > > > > > > > > > > >> > >> > >> > > > > > > > on
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > switches to 20
> > > instances.
> > > > > The
> > > > > > > > > request
> > > > > > > > > > > rate
> > > > > > > > > > > >> > will
> > > > > > > > > > > >> > >> > >> likely
> > > > > > > > > > > >> > >> > >> > > > > double,
> > > > > > > > > > > >> > >> > >> > > > > > > but
> > > > > > > > > > > >> > >> > >> > > > > > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > actually load on the
> > > > broker
> > > > > > may
> > > > > > > > not
> > > > > > > > > > > double
> > > > > > > > > > > >> > >> since
> > > > > > > > > > > >> > >> > >> each
> > > > > > > > > > > >> > >> > >> > > fetch
> > > > > > > > > > > >> > >> > >> > > > > > > request
> > > > > > > > > > > >> > >> > >> > > > > > > > > > only
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > contains half of the
> > > > > > partitions.
> > > > > > > > > > Request
> > > > > > > > > > > >> rate
> > > > > > > > > > > >> > >> > quota
> > > > > > > > > > > >> > >> > >> may
> > > > > > > > > > > >> > >> > >> > > not
> > > > > > > > > > > >> > >> > >> > > > > be
> > > > > > > > > > > >> > >> > >> > > > > > > easy
> > > > > > > > > > > >> > >> > >> > > > > > > > > to
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > configure in this
> > case.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > What we really want
> is
> > > to
> > > > be
> > > > > > > able
> > > > > > > > to
> > > > > > > > > > > >> prevent
> > > > > > > > > > > >> > a
> > > > > > > > > > > >> > >> > >> client
> > > > > > > > > > > >> > >> > >> > > from
> > > > > > > > > > > >> > >> > >> > > > > > using
> > > > > > > > > > > >> > >> > >> > > > > > > > too
> > > > > > > > > > > >> > >> > >> > > > > > > > > > much
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > of the server side
> > > > > resources.
> > > > > > In
> > > > > > > > > this
> > > > > > > > > > > >> > >> particular
> > > > > > > > > > > >> > >> > >> KIP,
> > > > > > > > > > > >> > >> > >> > > this
> > > > > > > > > > > >> > >> > >> > > > > > > resource
> > > > > > > > > > > >> > >> > >> > > > > > > > > is
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > capacity of the
> > request
> > > > > > handler
> > > > > > > > > > > threads. I
> > > > > > > > > > > >> > >> agree
> > > > > > > > > > > >> > >> > >> that
> > > > > > > > > > > >> > >> > >> > it
> > > > > > > > > > > >> > >> > >> > > > may
> > > > > > > > > > > >> > >> > >> > > > > > not
> > > > > > > > > > > >> > >> > >> > > > > > > be
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > intuitive for the
> > users
> > > to
> > > > > > > > determine
> > > > > > > > > > how
> > > > > > > > > > > >> to
> > > > > > > > > > > >> > set
> > > > > > > > > > > >> > >> > the
> > > > > > > > > > > >> > >> > >> > right
> > > > > > > > > > > >> > >> > >> > > > > > limit.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > However,
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > this is not
> completely
> > > new
> > > > > and
> > > > > > > has
> > > > > > > > > > been
> > > > > > > > > > > >> done
> > > > > > > > > > > >> > in
> > > > > > > > > > > >> > >> > the
> > > > > > > > > > > >> > >> > >> > > > container
> > > > > > > > > > > >> > >> > >> > > > > > > world
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > already. For
> example,
> > > > Linux
> > > > > > > > cgroup (
> > > > > > > > > > > >> > >> > >> > > > > https://access.redhat.com/
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > >
> > > > > documentation/en-US/Red_Hat_En
> > > > > > > > > > > >> > >> > >> terprise_Linux/6/html/
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > >
> > > > > Resource_Management_Guide/sec-
> > > > > > > > > > cpu.html)
> > > > > > > > > > > >> has
> > > > > > > > > > > >> > >> the
> > > > > > > > > > > >> > >> > >> > concept
> > > > > > > > > > > >> > >> > >> > > of
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > cpu.cfs_quota_us,
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > which specifies the
> > > total
> > > > > > amount
> > > > > > > > of
> > > > > > > > > > time
> > > > > > > > > > > >> in
> > > > > > > > > > > >> > >> > >> > microseconds
> > > > > > > > > > > >> > >> > >> > > > for
> > > > > > > > > > > >> > >> > >> > > > > > > which
> > > > > > > > > > > >> > >> > >> > > > > > > > > all
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > tasks in a cgroup
> can
> > > run
> > > > > > > during a
> > > > > > > > > one
> > > > > > > > > > > >> second
> > > > > > > > > > > >> > >> > >> period.
> > > > > > > > > > > >> > >> > >> > We
> > > > > > > > > > > >> > >> > >> > > > can
> > > > > > > > > > > >> > >> > >> > > > > > > > > > potentially
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > model the request
> > > handler
> > > > > > > threads
> > > > > > > > > in a
> > > > > > > > > > > >> > similar
> > > > > > > > > > > >> > >> > way.
> > > > > > > > > > > >> > >> > >> For
> > > > > > > > > > > >> > >> > >> > > > > > example,
> > > > > > > > > > > >> > >> > >> > > > > > > > each
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > request handler
> thread
> > > can
> > > > > be
> > > > > > 1
> > > > > > > > > > request
> > > > > > > > > > > >> > handler
> > > > > > > > > > > >> > >> > unit
> > > > > > > > > > > >> > >> > >> > and
> > > > > > > > > > > >> > >> > >> > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > admin
> > > > > > > > > > > >> > >> > >> > > > > > > > > can
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > configure a limit on
> > how
> > > > > many
> > > > > > > > units
> > > > > > > > > > (say
> > > > > > > > > > > >> > 0.01)
> > > > > > > > > > > >> > >> a
> > > > > > > > > > > >> > >> > >> client
> > > > > > > > > > > >> > >> > >> > > can
> > > > > > > > > > > >> > >> > >> > > > > > have.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > Regarding not
> > throttling
> > > > the
> > > > > > > > > internal
> > > > > > > > > > > >> broker
> > > > > > > > > > > >> > to
> > > > > > > > > > > >> > >> > >> broker
> > > > > > > > > > > >> > >> > >> > > > > > requests.
> > > > > > > > > > > >> > >> > >> > > > > > > We
> > > > > > > > > > > >> > >> > >> > > > > > > > > > could
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > do that.
> > Alternatively,
> > > we
> > > > > > could
> > > > > > > > > just
> > > > > > > > > > > let
> > > > > > > > > > > >> the
> > > > > > > > > > > >> > >> > admin
> > > > > > > > > > > >> > >> > >> > > > > configure a
> > > > > > > > > > > >> > >> > >> > > > > > > > high
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > limit
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > for the kafka user
> (it
> > > may
> > > > > not
> > > > > > > be
> > > > > > > > > able
> > > > > > > > > > > to
> > > > > > > > > > > >> do
> > > > > > > > > > > >> > >> that
> > > > > > > > > > > >> > >> > >> > easily
> > > > > > > > > > > >> > >> > >> > > > > based
> > > > > > > > > > > >> > >> > >> > > > > > on
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > clientId
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > though).
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > Ideally we want to
> be
> > > able
> > > > > to
> > > > > > > > > protect
> > > > > > > > > > > the
> > > > > > > > > > > >> > >> > >> utilization
> > > > > > > > > > > >> > >> > >> > of
> > > > > > > > > > > >> > >> > >> > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > network
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > thread
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > pool too. The
> > difficult
> > > is
> > > > > > > mostly
> > > > > > > > > what
> > > > > > > > > > > >> Rajini
> > > > > > > > > > > >> > >> > said:
> > > > > > > > > > > >> > >> > >> (1)
> > > > > > > > > > > >> > >> > >> > > The
> > > > > > > > > > > >> > >> > >> > > > > > > > mechanism
> > > > > > > > > > > >> > >> > >> > > > > > > > > > for
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > throttling the
> > requests
> > > is
> > > > > > > through
> > > > > > > > > > > >> Purgatory
> > > > > > > > > > > >> > >> and
> > > > > > > > > > > >> > >> > we
> > > > > > > > > > > >> > >> > >> > will
> > > > > > > > > > > >> > >> > >> > > > have
> > > > > > > > > > > >> > >> > >> > > > > > to
> > > > > > > > > > > >> > >> > >> > > > > > > > > think
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > through how to
> > integrate
> > > > > that
> > > > > > > into
> > > > > > > > > the
> > > > > > > > > > > >> > network
> > > > > > > > > > > >> > >> > >> layer.
> > > > > > > > > > > >> > >> > >> > > (2)
> > > > > > > > > > > >> > >> > >> > > > In
> > > > > > > > > > > >> > >> > >> > > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > > network
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > layer, currently we
> > know
> > > > the
> > > > > > > user,
> > > > > > > > > but
> > > > > > > > > > > not
> > > > > > > > > > > >> > the
> > > > > > > > > > > >> > >> > >> clientId
> > > > > > > > > > > >> > >> > >> > > of
> > > > > > > > > > > >> > >> > >> > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > request.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > So,
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > it's a bit tricky to
> > > > > throttle
> > > > > > > > based
> > > > > > > > > on
> > > > > > > > > > > >> > clientId
> > > > > > > > > > > >> > >> > >> there.
> > > > > > > > > > > >> > >> > >> > > > Plus,
> > > > > > > > > > > >> > >> > >> > > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > > byteOut
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > quota can already
> > > protect
> > > > > the
> > > > > > > > > network
> > > > > > > > > > > >> thread
> > > > > > > > > > > >> > >> > >> > utilization
> > > > > > > > > > > >> > >> > >> > > > for
> > > > > > > > > > > >> > >> > >> > > > > > > fetch
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > requests. So, if we
> > > can't
> > > > > > figure
> > > > > > > > out
> > > > > > > > > > > this
> > > > > > > > > > > >> > part
> > > > > > > > > > > >> > >> > right
> > > > > > > > > > > >> > >> > >> > now,
> > > > > > > > > > > >> > >> > >> > > > > just
> > > > > > > > > > > >> > >> > >> > > > > > > > > focusing
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > on
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > the request handling
> > > > threads
> > > > > > for
> > > > > > > > > this
> > > > > > > > > > > KIP
> > > > > > > > > > > >> is
> > > > > > > > > > > >> > >> > still a
> > > > > > > > > > > >> > >> > >> > > useful
> > > > > > > > > > > >> > >> > >> > > > > > > > feature.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > Thanks,
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > Jun
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > On Tue, Feb 21, 2017
> > at
> > > > 4:27
> > > > > > AM,
> > > > > > > > > > Rajini
> > > > > > > > > > > >> > >> Sivaram <
> > > > > > > > > > > >> > >> > >> > > > > > > > > > rajinisiva...@gmail.com
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > wrote:
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > Thank you all for
> > the
> > > > > > > feedback.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > Jay: I have
> removed
> > > > > > exemption
> > > > > > > > for
> > > > > > > > > > > >> consumer
> > > > > > > > > > > >> > >> > >> heartbeat
> > > > > > > > > > > >> > >> > >> > > etc.
> > > > > > > > > > > >> > >> > >> > > > > > Agree
> > > > > > > > > > > >> > >> > >> > > > > > > > > that
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > protecting the
> > cluster
> > > > is
> > > > > > more
> > > > > > > > > > > important
> > > > > > > > > > > >> > than
> > > > > > > > > > > >> > >> > >> > > protecting
> > > > > > > > > > > >> > >> > >> > > > > > > > individual
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > apps.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > Have retained the
> > > > > exemption
> > > > > > > for
> > > > > > > > > > > >> > >> > >> > > StopReplicat/LeaderAndIsr
> > > > > > > > > > > >> > >> > >> > > > > > etc,
> > > > > > > > > > > >> > >> > >> > > > > > > > > these
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > are
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > throttled only if
> > > > > > > authorization
> > > > > > > > > > fails
> > > > > > > > > > > >> (so
> > > > > > > > > > > >> > >> can't
> > > > > > > > > > > >> > >> > be
> > > > > > > > > > > >> > >> > >> > used
> > > > > > > > > > > >> > >> > >> > > > for
> > > > > > > > > > > >> > >> > >> > > > > > DoS
> > > > > > > > > > > >> > >> > >> > > > > > > > > > attacks
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > in
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > a secure cluster,
> > but
> > > > > allows
> > > > > > > > > > > >> inter-broker
> > > > > > > > > > > >> > >> > >> requests to
> > > > > > > > > > > >> > >> > >> > > > > > complete
> > > > > > > > > > > >> > >> > >> > > > > > > > > > without
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > delays).
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > I will wait
> another
> > > day
> > > > to
> > > > > > see
> > > > > > > > if
> > > > > > > > > > > these
> > > > > > > > > > > >> is
> > > > > > > > > > > >> > >> any
> > > > > > > > > > > >> > >> > >> > > objection
> > > > > > > > > > > >> > >> > >> > > > to
> > > > > > > > > > > >> > >> > >> > > > > > > > quotas
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > based
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > on
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > request processing
> > > time
> > > > > (as
> > > > > > > > > opposed
> > > > > > > > > > to
> > > > > > > > > > > >> > >> request
> > > > > > > > > > > >> > >> > >> rate)
> > > > > > > > > > > >> > >> > >> > > and
> > > > > > > > > > > >> > >> > >> > > > if
> > > > > > > > > > > >> > >> > >> > > > > > > there
> > > > > > > > > > > >> > >> > >> > > > > > > > > are
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > no
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > objections, I will
> > > > revert
> > > > > to
> > > > > > > the
> > > > > > > > > > > >> original
> > > > > > > > > > > >> > >> > proposal
> > > > > > > > > > > >> > >> > >> > with
> > > > > > > > > > > >> > >> > >> > > > > some
> > > > > > > > > > > >> > >> > >> > > > > > > > > changes.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > The original
> > proposal
> > > > was
> > > > > > only
> > > > > > > > > > > including
> > > > > > > > > > > >> > the
> > > > > > > > > > > >> > >> > time
> > > > > > > > > > > >> > >> > >> > used
> > > > > > > > > > > >> > >> > >> > > by
> > > > > > > > > > > >> > >> > >> > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > request
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > handler threads
> > (that
> > > > made
> > > > > > > > > > calculation
> > > > > > > > > > > >> > >> easy). I
> > > > > > > > > > > >> > >> > >> think
> > > > > > > > > > > >> > >> > >> > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > suggestion
> > > > > > > > > > > >> > >> > >> > > > > > > > > > is
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > to
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > include the time
> > spent
> > > > in
> > > > > > the
> > > > > > > > > > network
> > > > > > > > > > > >> > >> threads as
> > > > > > > > > > > >> > >> > >> well
> > > > > > > > > > > >> > >> > >> > > > since
> > > > > > > > > > > >> > >> > >> > > > > > > that
> > > > > > > > > > > >> > >> > >> > > > > > > > > may
> > > > > > > > > > > >> > >> > >> > > > > > > > > > be
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > significant. As
> Jay
> > > > > pointed
> > > > > > > out,
> > > > > > > > > it
> > > > > > > > > > is
> > > > > > > > > > > >> more
> > > > > > > > > > > >> > >> > >> > complicated
> > > > > > > > > > > >> > >> > >> > > > to
> > > > > > > > > > > >> > >> > >> > > > > > > > > calculate
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > total available
> CPU
> > > time
> > > > > and
> > > > > > > > > convert
> > > > > > > > > > > to
> > > > > > > > > > > >> a
> > > > > > > > > > > >> > >> ratio
> > > > > > > > > > > >> > >> > >> when
> > > > > > > > > > > >> > >> > >> > > > there
> > > > > > > > > > > >> > >> > >> > > > > > *m*
> > > > > > > > > > > >> > >> > >> > > > > > > > I/O
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > threads
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > and *n* network
> > > threads.
> > > > > > > > > > > >> > >> > >> > ThreadMXBean#getThreadCPUTime(
> > > > > > > > > > > >> > >> > >> > > )
> > > > > > > > > > > >> > >> > >> > > > > may
> > > > > > > > > > > >> > >> > >> > > > > > > > give
> > > > > > > > > > > >> > >> > >> > > > > > > > > us
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > what
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > we want, but it
> can
> > be
> > > > > very
> > > > > > > > > > expensive
> > > > > > > > > > > on
> > > > > > > > > > > >> > some
> > > > > > > > > > > >> > >> > >> > > platforms.
> > > > > > > > > > > >> > >> > >> > > > As
> > > > > > > > > > > >> > >> > >> > > > > > > > Becket
> > > > > > > > > > > >> > >> > >> > > > > > > > > > and
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > Guozhang have
> > pointed
> > > > out,
> > > > > > we
> > > > > > > do
> > > > > > > > > > have
> > > > > > > > > > > >> > several
> > > > > > > > > > > >> > >> > time
> > > > > > > > > > > >> > >> > >> > > > > > measurements
> > > > > > > > > > > >> > >> > >> > > > > > > > > > already
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > for
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > generating metrics
> > > that
> > > > we
> > > > > > > could
> > > > > > > > > > use,
> > > > > > > > > > > >> > though
> > > > > > > > > > > >> > >> we
> > > > > > > > > > > >> > >> > >> might
> > > > > > > > > > > >> > >> > >> > > > want
> > > > > > > > > > > >> > >> > >> > > > > to
> > > > > > > > > > > >> > >> > >> > > > > > > > > switch
> > > > > > > > > > > >> > >> > >> > > > > > > > > > to
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > nanoTime() instead
> > of
> > > > > > > > > > > >> currentTimeMillis()
> > > > > > > > > > > >> > >> since
> > > > > > > > > > > >> > >> > >> some
> > > > > > > > > > > >> > >> > >> > of
> > > > > > > > > > > >> > >> > >> > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > values
> > > > > > > > > > > >> > >> > >> > > > > > > > > > for
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > small requests may
> > be
> > > <
> > > > > 1ms.
> > > > > > > But
> > > > > > > > > > > rather
> > > > > > > > > > > >> > than
> > > > > > > > > > > >> > >> add
> > > > > > > > > > > >> > >> > >> up
> > > > > > > > > > > >> > >> > >> > the
> > > > > > > > > > > >> > >> > >> > > > > time
> > > > > > > > > > > >> > >> > >> > > > > > > > spent
> > > > > > > > > > > >> > >> > >> > > > > > > > > in
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > I/O
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > thread and network
> > > > thread,
> > > > > > > > > wouldn't
> > > > > > > > > > it
> > > > > > > > > > > >> be
> > > > > > > > > > > >> > >> better
> > > > > > > > > > > >> > >> > >> to
> > > > > > > > > > > >> > >> > >> > > > convert
> > > > > > > > > > > >> > >> > >> > > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > time
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > spent
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > on each thread
> into
> > a
> > > > > > separate
> > > > > > > > > > ratio?
> > > > > > > > > > > >> UserA
> > > > > > > > > > > >> > >> has
> > > > > > > > > > > >> > >> > a
> > > > > > > > > > > >> > >> > >> > > request
> > > > > > > > > > > >> > >> > >> > > > > > quota
> > > > > > > > > > > >> > >> > >> > > > > > > > of
> > > > > > > > > > > >> > >> > >> > > > > > > > > > 5%.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > Can
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > we take that to
> mean
> > > > that
> > > > > > > UserA
> > > > > > > > > can
> > > > > > > > > > > use
> > > > > > > > > > > >> 5%
> > > > > > > > > > > >> > of
> > > > > > > > > > > >> > >> > the
> > > > > > > > > > > >> > >> > >> > time
> > > > > > > > > > > >> > >> > >> > > on
> > > > > > > > > > > >> > >> > >> > > > > > > network
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > threads
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > and 5% of the time
> > on
> > > > I/O
> > > > > > > > threads?
> > > > > > > > > > If
> > > > > > > > > > > >> > either
> > > > > > > > > > > >> > >> is
> > > > > > > > > > > >> > >> > >> > > exceeded,
> > > > > > > > > > > >> > >> > >> > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > > response
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > is
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > throttled - it
> would
> > > > mean
> > > > > > > > > > maintaining
> > > > > > > > > > > >> two
> > > > > > > > > > > >> > >> sets
> > > > > > > > > > > >> > >> > of
> > > > > > > > > > > >> > >> > >> > > metrics
> > > > > > > > > > > >> > >> > >> > > > > for
> > > > > > > > > > > >> > >> > >> > > > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > two
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > durations, but
> would
> > > > > result
> > > > > > in
> > > > > > > > > more
> > > > > > > > > > > >> > >> meaningful
> > > > > > > > > > > >> > >> > >> > ratios.
> > > > > > > > > > > >> > >> > >> > > We
> > > > > > > > > > > >> > >> > >> > > > > > could
> > > > > > > > > > > >> > >> > >> > > > > > > > > > define
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > two
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > quota limits
> (UserA
> > > has
> > > > 5%
> > > > > > of
> > > > > > > > > > request
> > > > > > > > > > > >> > threads
> > > > > > > > > > > >> > >> > and
> > > > > > > > > > > >> > >> > >> 10%
> > > > > > > > > > > >> > >> > >> > > of
> > > > > > > > > > > >> > >> > >> > > > > > > network
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > threads),
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > but that seems
> > > > unnecessary
> > > > > > and
> > > > > > > > > > harder
> > > > > > > > > > > to
> > > > > > > > > > > >> > >> explain
> > > > > > > > > > > >> > >> > >> to
> > > > > > > > > > > >> > >> > >> > > > users.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > Back to why and
> how
> > > > quotas
> > > > > > are
> > > > > > > > > > applied
> > > > > > > > > > > >> to
> > > > > > > > > > > >> > >> > network
> > > > > > > > > > > >> > >> > >> > > thread
> > > > > > > > > > > >> > >> > >> > > > > > > > > utilization:
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > a) In the case of
> > > fetch,
> > > > > > the
> > > > > > > > time
> > > > > > > > > > > >> spent in
> > > > > > > > > > > >> > >> the
> > > > > > > > > > > >> > >> > >> > network
> > > > > > > > > > > >> > >> > >> > > > > > thread
> > > > > > > > > > > >> > >> > >> > > > > > > > may
> > > > > > > > > > > >> > >> > >> > > > > > > > > be
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > significant and I
> > can
> > > > see
> > > > > > the
> > > > > > > > need
> > > > > > > > > > to
> > > > > > > > > > > >> > include
> > > > > > > > > > > >> > >> > >> this.
> > > > > > > > > > > >> > >> > >> > Are
> > > > > > > > > > > >> > >> > >> > > > > there
> > > > > > > > > > > >> > >> > >> > > > > > > > other
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > requests where the
> > > > network
> > > > > > > > thread
> > > > > > > > > > > >> > >> utilization is
> > > > > > > > > > > >> > >> > >> > > > > significant?
> > > > > > > > > > > >> > >> > >> > > > > > > In
> > > > > > > > > > > >> > >> > >> > > > > > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > case
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > of fetch, request
> > > > handler
> > > > > > > thread
> > > > > > > > > > > >> > utilization
> > > > > > > > > > > >> > >> > would
> > > > > > > > > > > >> > >> > >> > > > throttle
> > > > > > > > > > > >> > >> > >> > > > > > > > clients
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > with
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > high request rate,
> > low
> > > > > data
> > > > > > > > volume
> > > > > > > > > > and
> > > > > > > > > > > >> > fetch
> > > > > > > > > > > >> > >> > byte
> > > > > > > > > > > >> > >> > >> > rate
> > > > > > > > > > > >> > >> > >> > > > > quota
> > > > > > > > > > > >> > >> > >> > > > > > > will
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > throttle
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > clients with high
> > data
> > > > > > volume.
> > > > > > > > > > Network
> > > > > > > > > > > >> > thread
> > > > > > > > > > > >> > >> > >> > > utilization
> > > > > > > > > > > >> > >> > >> > > > > is
> > > > > > > > > > > >> > >> > >> > > > > > > > > perhaps
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > proportional to
> the
> > > data
> > > > > > > > volume. I
> > > > > > > > > > am
> > > > > > > > > > > >> > >> wondering
> > > > > > > > > > > >> > >> > >> if we
> > > > > > > > > > > >> > >> > >> > > > even
> > > > > > > > > > > >> > >> > >> > > > > > need
> > > > > > > > > > > >> > >> > >> > > > > > > > to
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > throttle
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > based on network
> > > thread
> > > > > > > > > utilization
> > > > > > > > > > or
> > > > > > > > > > > >> > >> whether
> > > > > > > > > > > >> > >> > the
> > > > > > > > > > > >> > >> > >> > data
> > > > > > > > > > > >> > >> > >> > > > > > volume
> > > > > > > > > > > >> > >> > >> > > > > > > > > quota
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > covers
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > this case.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > b) At the moment,
> we
> > > > > record
> > > > > > > and
> > > > > > > > > > check
> > > > > > > > > > > >> for
> > > > > > > > > > > >> > >> quota
> > > > > > > > > > > >> > >> > >> > > violation
> > > > > > > > > > > >> > >> > >> > > > > at
> > > > > > > > > > > >> > >> > >> > > > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > same
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > time.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > If a quota is
> > > violated,
> > > > > the
> > > > > > > > > response
> > > > > > > > > > > is
> > > > > > > > > > > >> > >> delayed.
> > > > > > > > > > > >> > >> > >> > Using
> > > > > > > > > > > >> > >> > >> > > > > Jay'e
> > > > > > > > > > > >> > >> > >> > > > > > > > > example
> > > > > > > > > > > >> > >> > >> > > > > > > > > > of
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > disk reads for
> > fetches
> > > > > > > happening
> > > > > > > > > in
> > > > > > > > > > > the
> > > > > > > > > > > >> > >> network
> > > > > > > > > > > >> > >> > >> > thread,
> > > > > > > > > > > >> > >> > >> > > > We
> > > > > > > > > > > >> > >> > >> > > > > > > can't
> > > > > > > > > > > >> > >> > >> > > > > > > > > > record
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > and
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > delay a response
> > after
> > > > the
> > > > > > > disk
> > > > > > > > > > reads.
> > > > > > > > > > > >> We
> > > > > > > > > > > >> > >> could
> > > > > > > > > > > >> > >> > >> > record
> > > > > > > > > > > >> > >> > >> > > > the
> > > > > > > > > > > >> > >> > >> > > > > > time
> > > > > > > > > > > >> > >> > >> > > > > > > > > spent
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > on
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > the network thread
> > > when
> > > > > the
> > > > > > > > > response
> > > > > > > > > > > is
> > > > > > > > > > > >> > >> complete
> > > > > > > > > > > >> > >> > >> and
> > > > > > > > > > > >> > >> > >> > > > > > introduce
> > > > > > > > > > > >> > >> > >> > > > > > > a
> > > > > > > > > > > >> > >> > >> > > > > > > > > > delay
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > for
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > handling a
> > subsequent
> > > > > > request
> > > > > > > > > > > (separate
> > > > > > > > > > > >> out
> > > > > > > > > > > >> > >> > >> recording
> > > > > > > > > > > >> > >> > >> > > and
> > > > > > > > > > > >> > >> > >> > > > > > quota
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > violation
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > handling in the
> case
> > > of
> > > > > > > network
> > > > > > > > > > thread
> > > > > > > > > > > >> > >> > overload).
> > > > > > > > > > > >> > >> > >> > Does
> > > > > > > > > > > >> > >> > >> > > > that
> > > > > > > > > > > >> > >> > >> > > > > > > make
> > > > > > > > > > > >> > >> > >> > > > > > > > > > sense?
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > Regards,
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > Rajini
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > On Tue, Feb 21,
> 2017
> > > at
> > > > > 2:58
> > > > > > > AM,
> > > > > > > > > > > Becket
> > > > > > > > > > > >> > Qin <
> > > > > > > > > > > >> > >> > >> > > > > > > > becket....@gmail.com>
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > wrote:
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > Hey Jay,
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > Yeah, I agree
> that
> > > > > > enforcing
> > > > > > > > the
> > > > > > > > > > CPU
> > > > > > > > > > > >> time
> > > > > > > > > > > >> > >> is a
> > > > > > > > > > > >> > >> > >> > little
> > > > > > > > > > > >> > >> > >> > > > > > > tricky. I
> > > > > > > > > > > >> > >> > >> > > > > > > > > am
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > thinking
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > that maybe we
> can
> > > use
> > > > > the
> > > > > > > > > existing
> > > > > > > > > > > >> > request
> > > > > > > > > > > >> > >> > >> > > statistics.
> > > > > > > > > > > >> > >> > >> > > > > They
> > > > > > > > > > > >> > >> > >> > > > > > > are
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > already
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > very detailed so
> > we
> > > > can
> > > > > > > > probably
> > > > > > > > > > see
> > > > > > > > > > > >> the
> > > > > > > > > > > >> > >> > >> > approximate
> > > > > > > > > > > >> > >> > >> > > > CPU
> > > > > > > > > > > >> > >> > >> > > > > > time
> > > > > > > > > > > >> > >> > >> > > > > > > > > from
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > it,
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > e.g.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > something like
> > > > > > (total_time -
> > > > > > > > > > > >> > >> > >> > > > request/response_queue_time
> > > > > > > > > > > >> > >> > >> > > > > -
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > remote_time).
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > I agree with
> > > Guozhang
> > > > > that
> > > > > > > > when
> > > > > > > > > a
> > > > > > > > > > > >> user is
> > > > > > > > > > > >> > >> > >> throttled
> > > > > > > > > > > >> > >> > >> > > it
> > > > > > > > > > > >> > >> > >> > > > is
> > > > > > > > > > > >> > >> > >> > > > > > > > likely
> > > > > > > > > > > >> > >> > >> > > > > > > > > > that
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > we
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > need to see if
> > > > anything
> > > > > > has
> > > > > > > > went
> > > > > > > > > > > wrong
> > > > > > > > > > > >> > >> first,
> > > > > > > > > > > >> > >> > >> and
> > > > > > > > > > > >> > >> > >> > if
> > > > > > > > > > > >> > >> > >> > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > users
> > > > > > > > > > > >> > >> > >> > > > > > > > > are
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > well
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > behaving and
> just
> > > need
> > > > > > more
> > > > > > > > > > > >> resources, we
> > > > > > > > > > > >> > >> will
> > > > > > > > > > > >> > >> > >> have
> > > > > > > > > > > >> > >> > >> > > to
> > > > > > > > > > > >> > >> > >> > > > > bump
> > > > > > > > > > > >> > >> > >> > > > > > > up
> > > > > > > > > > > >> > >> > >> > > > > > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > quota
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > for them. It is
> > true
> > > > > that
> > > > > > > > > > > >> pre-allocating
> > > > > > > > > > > >> > >> CPU
> > > > > > > > > > > >> > >> > >> time
> > > > > > > > > > > >> > >> > >> > > quota
> > > > > > > > > > > >> > >> > >> > > > > > > > precisely
> > > > > > > > > > > >> > >> > >> > > > > > > > > > for
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > users is
> > difficult.
> > > So
> > > > > in
> > > > > > > > > practice
> > > > > > > > > > > it
> > > > > > > > > > > >> > would
> > > > > > > > > > > >> > >> > >> > probably
> > > > > > > > > > > >> > >> > >> > > be
> > > > > > > > > > > >> > >> > >> > > > > > more
> > > > > > > > > > > >> > >> > >> > > > > > > > like
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > first
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > set
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > a relative high
> > > > > protective
> > > > > > > CPU
> > > > > > > > > > time
> > > > > > > > > > > >> quota
> > > > > > > > > > > >> > >> for
> > > > > > > > > > > >> > >> > >> > > everyone
> > > > > > > > > > > >> > >> > >> > > > > and
> > > > > > > > > > > >> > >> > >> > > > > > > > > increase
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > that
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > for some
> > individual
> > > > > > clients
> > > > > > > on
> > > > > > > > > > > demand.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > Jiangjie
> (Becket)
> > > Qin
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > On Mon, Feb 20,
> > 2017
> > > > at
> > > > > > 5:48
> > > > > > > > PM,
> > > > > > > > > > > >> Guozhang
> > > > > > > > > > > >> > >> > Wang <
> > > > > > > > > > > >> > >> > >> > > > > > > > > wangg...@gmail.com
> > > > > > > > > > > >> > >> > >> > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > wrote:
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > > This is a
> great
> > > > > > proposal,
> > > > > > > > glad
> > > > > > > > > > to
> > > > > > > > > > > >> see
> > > > > > > > > > > >> > it
> > > > > > > > > > > >> > >> > >> > happening.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > > I am inclined
> to
> > > the
> > > > > CPU
> > > > > > > > > > > >> throttling, or
> > > > > > > > > > > >> > >> more
> > > > > > > > > > > >> > >> > >> > > > > specifically
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > processing
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > time
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > > ratio instead
> of
> > > the
> > > > > > > request
> > > > > > > > > > rate
> > > > > > > > > > > >> > >> throttling
> > > > > > > > > > > >> > >> > >> as
> > > > > > > > > > > >> > >> > >> > > well.
> > > > > > > > > > > >> > >> > >> > > > > > > Becket
> > > > > > > > > > > >> > >> > >> > > > > > > > > has
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > very
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > well
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > > summed my
> > > rationales
> > > > > > > above,
> > > > > > > > > and
> > > > > > > > > > > one
> > > > > > > > > > > >> > >> thing to
> > > > > > > > > > > >> > >> > >> add
> > > > > > > > > > > >> > >> > >> > > here
> > > > > > > > > > > >> > >> > >> > > > > is
> > > > > > > > > > > >> > >> > >> > > > > > > that
> > > > > > > > > > > >> > >> > >> > > > > > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > former
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > > has a good
> > support
> > > > for
> > > > > > > both
> > > > > > > > > > > >> "protecting
> > > > > > > > > > > >> > >> > >> against
> > > > > > > > > > > >> > >> > >> > > rogue
> > > > > > > > > > > >> > >> > >> > > > > > > > clients"
> > > > > > > > > > > >> > >> > >> > > > > > > > > as
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > well
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > as
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > > "utilizing a
> > > cluster
> > > > > for
> > > > > > > > > > > >> multi-tenancy
> > > > > > > > > > > >> > >> > usage":
> > > > > > > > > > > >> > >> > >> > when
> > > > > > > > > > > >> > >> > >> > > > > > > thinking
> > > > > > > > > > > >> > >> > >> > > > > > > > > > about
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > how
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > to
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > > explain this
> to
> > > the
> > > > > end
> > > > > > > > > users, I
> > > > > > > > > > > >> find
> > > > > > > > > > > >> > it
> > > > > > > > > > > >> > >> > >> actually
> > > > > > > > > > > >> > >> > >> > > > more
> > > > > > > > > > > >> > >> > >> > > > > > > > natural
> > > > > > > > > > > >> > >> > >> > > > > > > > > > than
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > > request rate
> > since
> > > > as
> > > > > > > > > mentioned
> > > > > > > > > > > >> above,
> > > > > > > > > > > >> > >> > >> different
> > > > > > > > > > > >> > >> > >> > > > > requests
> > > > > > > > > > > >> > >> > >> > > > > > > > will
> > > > > > > > > > > >> > >> > >> > > > > > > > > > have
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > quite
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > > different
> > "cost",
> > > > and
> > > > > > > Kafka
> > > > > > > > > > today
> > > > > > > > > > > >> > already
> > > > > > > > > > > >> > >> > have
> > > > > > > > > > > >> > >> > >> > > > various
> > > > > > > > > > > >> > >> > >> > > > > > > > request
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > types
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > > (produce,
> fetch,
> > > > > admin,
> > > > > > > > > > metadata,
> > > > > > > > > > > >> etc),
> > > > > > > > > > > >> > >> > >> because
> > > > > > > > > > > >> > >> > >> > of
> > > > > > > > > > > >> > >> > >> > > > that
> > > > > > > > > > > >> > >> > >> > > > > > the
> > > > > > > > > > > >> > >> > >> > > > > > > > > > request
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > rate
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > > throttling may
> > not
> > > > be
> > > > > as
> > > > > > > > > > effective
> > > > > > > > > > > >> > >> unless it
> > > > > > > > > > > >> > >> > >> is
> > > > > > > > > > > >> > >> > >> > set
> > > > > > > > > > > >> > >> > >> > > > > very
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > conservatively.
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > >
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > > Regarding to
> > user
> > > > > > > reactions
> > > > > > > > > when
> > > > > > > > > > > >> they
> > > > > > > > > > > >> > are
> > > > > > > > > > > >> > >> > >> > > throttled,
> > > > > > > > > > > >> > >> > >> > > > I
> > > > > > > > > > > >> > >> > >> > > > > > > think
> > > > > > > > > > > >> > >> > >> > > > > > > > it
> > > > > > > > > > > >> > >> > >> > > > > > > > > > may
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > differ
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > > case-by-case,
> > and
> > > > need
> > > > > > to
> > > > > > > be
> > > > > > > > > > > >> > discovered /
> > > > > > > > > > > >> > >> > >> guided
> > > > > > > > > > > >> > >> > >> > by
> > > > > > > > > > > >> > >> > >> > > > > > looking
> > > > > > > > > > > >> > >> > >> > > > > > > > at
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > relative
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > > metrics. So in
> > > other
> > > > > > words
> > > > > > > > > users
> > > > > > > > > > > >> would
> > > > > > > > > > > >> > >> not
> > > > > > > > > > > >> > >> > >> expect
> > > > > > > > > > > >> > >> > >> > > to
> > > > > > > > > > > >> > >> > >> > > > > get
> > > > > > > > > > > >> > >> > >> > > > > > > > > > additional
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > > information by
> > > > simply
> > > > > > > being
> > > > > > > > > told
> > > > > > > > > > > >> "hey,
> > > > > > > > > > > >> > >> you
> > > > > > > > > > > >> > >> > are
> > > > > > > > > > > >> > >> > >> > > > > > throttled",
> > > > > > > > > > > >> > >> > >> > > > > > > > > which
> > > > > > > > > > > >> > >> > >> > > > > > > > > > is
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > all
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > > what
> throttling
> > > > does;
> > > > > > they
> > > > > > > > > need
> > > > > > > > > > to
> > > > > > > > > > > >> > take a
> > > > > > > > > > > >> > >> > >> > follow-up
> > > > > > > > > > > >> > >> > >> > > > > step
> > > > > > > > > > > >> > >> > >> > > > > > > and
> > > > > > > > > > > >> > >> > >> > > > > > > > > see
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > "hmm,
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > I'm
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > > throttled
> > probably
> > > > > > because
> > > > > > > > of
> > > > > > > > > > ..",
> > > > > > > > > > > >> > which
> > > > > > > > > > > >> > >> is
> > > > > > > > > > > >> > >> > by
> > > > > > > > > > > >> > >> > >> > > > looking
> > > > > > > > > > > >> > >> > >> > > > > at
> > > > > > > > > > > >> > >> > >> > > > > > > > other
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > metric
> > > > > > > > > > > >> > >> > >> > > > > > > > > > > > > > > values: e.g.
> > > whether
> > > > > I'm
> > > > > > > > > > > bombarding
> > > > > > > > > > > >> the
> > > > > > > > > > > >> > >> > >> brokers
> > > > > > > > > > > >> > >> > >> > > with
> > > > > > > > > > > >> > >> > >> > > > >
> > > > > > > > > > > >>
> > > > > > > > > > > > ...
> > > > > > > > > > > >
> > > > > > > > > > > > [Message clipped]
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> >
> >
> > --
> > *Todd Palino*
> > Staff Site Reliability Engineer
> > Data Infrastructure Streaming
> >
> >
> >
> > linkedin.com/in/toddpalino
> >
>
--
*Todd Palino*
Staff Site Reliability Engineer
Data Infrastructure Streaming
linkedin.com/in/toddpalino
