>You really want Gary King or Dan Rosa to chime in, not me. I can rarely
keep the details straight. If they provide me with information to relay on
their behalf, I will be glad to.
Thanks, for the offer. How about forwarding my initial post. I had written the
points of interest to me, and I thi
>zIIP dispatching is the same as GP dispatching. ZIIPAWMT
has analogous parameters for GP (CCCAWMT) and zAAP (ZAAPAWMT).
Alternate wait management was created long before there were
specialty engines.
Thank, Jim, much appreciated.
Sorry, guys, for not reading the latest posts before writing mi
>I believe hyper dispatch is very different from zIIP dispatch. I stand by my
>assumption that GP dispatch is very different from zIIP dispatch, or why would
>there be the ZIIPAWMT parameter and have the comment about waking up after
>that interval to see if there is work. When non-zIIP work c
ftware is now a part of Syncsort.
-Original Message-
From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf
Of Ed Jaffe
Sent: Saturday, June 9, 2018 9:46 AM
To: IBM-MAIN@LISTSERV.UA.EDU
Subject: Re: AW: Re: Why are highly busy zIIPs worse than highly busy CPs?
On 6/9/2018 3:48 AM, Peter Hunkeler wrote:
First of all, the dispatcher code for ZIIP processing is not the same as the GP
dispatcher.
Do you know this, or is it just an assumption on your side? After all I read,
it still would't make sense to me.
The dispatcher is the dispatcher -- and it w
>First of all, the dispatcher code for ZIIP processing is not the same as the
>GP dispatcher.
Do you know this, or is it just an assumption on your side? After all I read,
it still would't make sense to me.
If you think of the "need help" process for the zIIP to be special, isn't there
a sim
>Some of this dispatcher design by IBM could be based on the assumption that
>all the work is SRB and will be high priority work and of short duration.
This doesn't sound correct to me. Client SRBs (preemptive SRBs) were invented
to have some work done in another address space at client priorit
>> Is it? If you think about Java, maybe. But when it comes to workload such as
>> DB2, Sort, Monitors, that have shifted more and more of its task towards
>> zIIPs, isn't this still the same workload?
>> --
>> Peter Hunkeler
>
>The zIIP-eligible criteria for choosing a subset of tasks to run on
>How prevalent are installations today where the CPs run at top speed, in other
>words at the same speed as zIIP engines?
I haven't got the faintest idea. We do, but that doesn't matter for this
discussion. I thought this is complex enough, so I take one part of complexity
out first: Differen
> the workload on the CP is totally different.
Is it? If you think about Java, maybe. But when it comes to workload such as
DB2, Sort, Monitors, that have shifted more and more of its task towards zIIPs,
isn't this still the same workload?
--
Peter Hunkeler
--
>... however, we were warned that 'some customers' were experiencing serious
>performance problems when zIIP eligible work spilled over to general CPs.
Yeah, that is what I read and hear also, and I have no reason not to believe
it. In fact, I suspect we've just been bitten by zIIP overload. How
3573?mt=2
Youtube channel: https://www.youtube.com/channel/UCu_65HaYgksbF6Q8SQ4oOvA
From: Peter Hunkeler
To: IBM-MAIN@LISTSERV.UA.EDU
Date: 07/06/2018 17:14
Subject: AW: Re: Why are highly busy zIIPs worse than highly busy
CPs?
Sent by:IBM Mainframe Discussion List
>Isn't "fall back to the CP" because one would typically want one's work to
run *somewhere* even if a zIIP were not available but perhaps a CP was?
If you meant no zIIPs are available to the LPAR (not configured or the CEC does
not have some), then there is no fall-back. Work units get queue
>Scheduling an SRB isn't cheap. I don't know whether that's why, but for
>whatever reason, IBM has built this "fall back to the CP" mechanism.
What falls back is still SRBs. The scheduling overhead has already been done
before.
--
Peter Hunkeler
---
>Once the delay is long enough, the CP does the work. They cost about 10X the
>price of zIIPs.
I understand the potential impact on the software bill zIIP-on-CP might have.
That is not the point I want to get a better understanding. I'm interested in
the technical aspects, only.
IMHO, from
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