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Re: sched : performance regression 24% between 4.4rc4 and 4.3 kernel

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Hi Rik,

I have reviewed the data and you are right. The trouble is that even
with 4.3 kernel there is 20% change that results will be bad. I have
repeated tests 100 times on 4.3 kernel over the night. In 20 cases I
see that runtime went up from 12 seconds to 28 seconds due to the
wrong NUMA placement. I will try to replay the bisect once again.

Jirka

On Tue, Dec 15, 2015 at 3:12 AM, Rik van Riel <riel@redhat.com> wrote:
> On 12/14/2015 06:52 PM, Jirka Hladky wrote:
>> Hi all,
>>
>> I have the results of bisecting:
>>
>> first bad commit: [973759c80db96ed4b4c5cb85ac7d48107f801371] Merge tag
>> 'v4.3-rc1' into sched/core, to refresh the branch
>>
>> Could you please have a look at this commit why it has caused the
>> performance regression when running 4 stream benchmarks in parallel on 4
>> NUMA node server?
>
> That is a merge commit. It contains no actual code changes.
>
>> Please let me know if you need additional data. git bisect log is bellow.
>
> It looks like "git bisect" may have led you astray.
>
> I am not sure what debugging tool to use to figure out which
> of the patches from some merged-in branch caused the issue,
> but hopefully one of the people reading this email know a trick.
>
> --
> All rights reversed
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Re: sched : performance regression 24% between 4.4rc4 and 4.3 kernel Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-12-12 08:10 +0100
  Re: sched : performance regression 24% between 4.4rc4 and 4.3 kernel Jirka Hladky <jhladky@redhat.com> - 2015-12-12 15:20 +0100
    Re: sched : performance regression 24% between 4.4rc4 and 4.3 kernel Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-12-12 15:40 +0100
      Re: sched : performance regression 24% between 4.4rc4 and 4.3 kernel Jirka Hladky <jhladky@redhat.com> - 2015-12-15 01:10 +0100
      Re: sched : performance regression 24% between 4.4rc4 and 4.3 kernel Jirka Hladky <jhladky@redhat.com> - 2015-12-15 01:10 +0100
      Re: sched : performance regression 24% between 4.4rc4 and 4.3 kernel Rik van Riel <riel@redhat.com> - 2015-12-15 03:20 +0100
        Re: sched : performance regression 24% between 4.4rc4 and 4.3 kernel Jirka Hladky <jhladky@redhat.com> - 2015-12-15 09:50 +0100
          Re: sched : performance regression 24% between 4.4rc4 and 4.3 kernel Jirka Hladky <jhladky@redhat.com> - 2015-12-16 14:00 +0100
            Re: sched : performance regression 24% between 4.4rc4 and 4.3 kernel Peter Zijlstra <peterz@infradead.org> - 2015-12-16 15:00 +0100
              Re: sched : performance regression 24% between 4.4rc4 and 4.3 kernel Jirka Hladky <jhladky@redhat.com> - 2015-12-16 18:10 +0100
                Re: sched : performance regression 24% between 4.4rc4 and 4.3 kernel Jirka Hladky <jhladky@redhat.com> - 2015-12-17 16:50 +0100
                Re: sched : performance regression 24% between 4.4rc4 and 4.3 kernel Mike Galbraith <umgwanakikbuti@gmail.com> - 2015-12-18 03:50 +0100

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