Re: [Cake] Possible BUG - parent backlog incorrectly updated in case of NET_XMIT_CN

2016-06-12 Thread Benjamin Cronce
4GiB back log is several orders of magnitude more than what you want for a 100Gb link. Unless you think this algorithm will be used for 1Zb/s links. 64bit is a bit overkill On Jun 12, 2016 2:04 PM, "Eric Dumazet" wrote: > On Sun, 2016-06-12 at 20:59 +0300, Jonathan Morton wrote: > > > Not so - un

Re: [Cake] Possible BUG - parent backlog incorrectly updated in case of NET_XMIT_CN

2016-06-12 Thread Eric Dumazet
On Sun, 2016-06-12 at 20:59 +0300, Jonathan Morton wrote: > Not so - unless you are very sure that q->backlog is the same size as > quantity. Obviously this is the case in all linux kernels so far. If someone plans to change this at one point, then yes, he/she has to fix this. > In an increas

Re: [Cake] Possible BUG - parent backlog incorrectly updated in case of NET_XMIT_CN

2016-06-12 Thread Eric Dumazet
On Sun, 2016-06-12 at 20:51 +0300, Jonathan Morton wrote: > > On 12 Jun, 2016, at 20:48, Eric Dumazet wrote: > > > >> A) In my failing to make sense of all the dialog around these patches > >> ( https://lwn.net/Articles/687617/ ), it sounds like this (inbound > >> and outbound) processing are st

Re: [Cake] Possible BUG - parent backlog incorrectly updated in case of NET_XMIT_CN

2016-06-12 Thread Jonathan Morton
>> And there’s also the problem that we might not need to drop packets as >> large as the incoming packet in order to fit the latter into the queue >> - so this corrected correction may be *negative* (the queue is longer >> than before) - but qdisc_tree_reduce_backlog() only takes an unsigned >> pa

Re: [Cake] Possible BUG - parent backlog incorrectly updated in case of NET_XMIT_CN

2016-06-12 Thread Jonathan Morton
> On 12 Jun, 2016, at 20:48, Eric Dumazet wrote: > >> A) In my failing to make sense of all the dialog around these patches >> ( https://lwn.net/Articles/687617/ ), it sounds like this (inbound >> and outbound) processing are still locked to a single thread, >> essentially? > > Om a router, th

Re: [Cake] Possible BUG - parent backlog incorrectly updated in case of NET_XMIT_CN

2016-06-12 Thread Eric Dumazet
On Sun, 2016-06-12 at 09:40 -0700, Dave Taht wrote: > Eric: > > Quick side question (from trying to understand the qdisc locking fixes > you recently landed in net-next) > > In the sqm-scripts, we are usually in a position where we are doing > both inbound and outbound rate limiting (htb + fq_cod

Re: [Cake] Possible BUG - parent backlog incorrectly updated in case of NET_XMIT_CN

2016-06-12 Thread Dave Taht
Eric: Quick side question (from trying to understand the qdisc locking fixes you recently landed in net-next) In the sqm-scripts, we are usually in a position where we are doing both inbound and outbound rate limiting (htb + fq_codel or cake). We typically run out of cpu or have mis-behavior on t

Re: [Cake] Possible BUG - parent backlog incorrectly updated in case of NET_XMIT_CN

2016-06-12 Thread Eric Dumazet
On Sat, 2016-06-11 at 19:41 +0300, Jonathan Morton wrote: > > On 11 Jun, 2016, at 12:11, Kevin Darbyshire-Bryant > > wrote: > > > > And now there's a version 2 of Eric's fix: > > http://marc.info/?l=linux-netdev&m=146507012302643&w=2 > > > > Does this change apply to cake? > > I suppose this

Re: [Cake] Possible BUG - parent backlog incorrectly updated in case of NET_XMIT_CN

2016-06-11 Thread Jonathan Morton
> On 11 Jun, 2016, at 12:11, Kevin Darbyshire-Bryant > wrote: > > And now there's a version 2 of Eric's fix: > http://marc.info/?l=linux-netdev&m=146507012302643&w=2 > > Does this change apply to cake? I suppose this answers the question of which packet’s size should be used in the correcti

Re: [Cake] Possible BUG - parent backlog incorrectly updated in case of NET_XMIT_CN

2016-06-11 Thread Kevin Darbyshire-Bryant
On 07/06/16 16:05, Kevin Darbyshire-Bryant wrote: On 07/06/16 15:50, Jonathan Morton wrote: On 7 Jun, 2016, at 14:20, Kevin Darbyshire-Bryant wrote: I had a nose at CAKE but couldn't quit work out if a similar issue is present but I suspect it is. Certainly if Eric can't get it right "M

Re: [Cake] Possible BUG - parent backlog incorrectly updated in case of NET_XMIT_CN

2016-06-07 Thread Kevin Darbyshire-Bryant
On 07/06/16 15:50, Jonathan Morton wrote: On 7 Jun, 2016, at 14:20, Kevin Darbyshire-Bryant wrote: I had a nose at CAKE but couldn't quit work out if a similar issue is present but I suspect it is. Certainly if Eric can't get it right "My prior attempt to fix the backlogs of parents failed

Re: [Cake] Possible BUG - parent backlog incorrectly updated in case of NET_XMIT_CN

2016-06-07 Thread Jonathan Morton
> On 7 Jun, 2016, at 14:20, Kevin Darbyshire-Bryant > wrote: > > I had a nose at CAKE but couldn't quit work out if a similar issue is present > but I suspect it is. Certainly if Eric can't get it right "My prior attempt > to fix the backlogs of parents failed." then it's not an 'obvious to s

[Cake] Possible BUG - parent backlog incorrectly updated in case of NET_XMIT_CN

2016-06-07 Thread Kevin Darbyshire-Bryant
Hi All, I was nosing through linux-netdev last night when I saw this fix for qdisc backlog reporting issues with NET_XMIT_CN in fq_codel: http://marc.info/?l=linux-netdev&m=146506223800713&w=2 I had a nose at CAKE but couldn't quit work out if a similar issue is present but I suspect it is.