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Re: Scheduler patches: 6x performance increase when system is under heavy load

From Alexandre-Xavier Labonté-Lamoureux <axdoomer@gmail.com>
Newsgroups linux.kernel
Subject Re: Scheduler patches: 6x performance increase when system is under heavy load
Date 2016-12-14 06:20 +0100
Message-ID <sOa8V-2mt-1@gated-at.bofh.it> (permalink)
References <sNkal-4fW-3@gated-at.bofh.it> <sNVCW-1NI-25@gated-at.bofh.it>
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> Which of the 4 patches does this?

I used all the 4 patches at the same time. Each patch fixes a
different bug. Would you like me to try each of them individually?
Were you already aware of each of these bugs?

> Also, what hypervisor are you using and what does the output of booting
> with "sched_debug" look like?

I was running the distro in VirualBox on Fedora. Here's the info from
/proc/sched_debug:
https://justpaste.it/11dhb
dmesg: https://justpaste.it/11dhr

> Lastly, can you reproduce on real hardware?

No. On real hardware, I tested in Ubuntu on an i7-4790 3.60GHz CPU
without disabling HT and I saw no difference between CFS, the patched
kernel and MuQSS. If I get to know a reason why one would be better
than the other, I'd take the time to test it on more hardware. I'm
curious how I got such a performance improvement in my VM.

On Tue, Dec 13, 2016 at 8:40 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> On Sun, Dec 11, 2016 at 04:41:51PM -0500, Alexandre-Xavier Labonté-Lamoureux wrote:
>>
>> Here are my results (using "time make -j32" on my VM that has 4 cores):
>>
>> Kernel 4.8.14
>>   real 26m56.151s
>>   user 79m52.472s
>>   sys 7m42.964s
>>
>> Same kernel, but patched:
>>   real 4m25.238s
>>   user 13m52.932s
>>   sys 1m25.820s
>>
>> I hope you guys will look into this.
>
> Which of the 4 patches does this?
>
> Also, what hypervisor are you using and what does the output of booting
> with "sched_debug" look like?
>
> Lastly, can you reproduce on real hardware?

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Thread

Scheduler patches: 6x performance increase when system is under heavy load Alexandre-Xavier Labonté-Lamoureux          <axdoomer@gmail.com> - 2016-12-11 22:50 +0100
  Re: Scheduler patches: 6x performance increase when system is under  heavy load Peter Zijlstra <peterz@infradead.org> - 2016-12-13 14:50 +0100
    Re: Scheduler patches: 6x performance increase when system is under  heavy load Alexandre-Xavier Labonté-Lamoureux          <axdoomer@gmail.com> - 2016-12-14 06:20 +0100
      Re: Scheduler patches: 6x performance increase when system is under  heavy load Peter Zijlstra <peterz@infradead.org> - 2016-12-20 15:10 +0100

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