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From: Andy Lutomirski <luto@amacapital.net>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>, Ingo Molnar <mingo@kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: Abysmal scheduler performance in Linus' tree?
Date: Wed, 6 Sep 2017 01:59:14 -0700
Message-ID: <877A43A3-AC8F-4D7C-88E4-8E3D36B1DAFA@amacapital.net> (raw)
In-Reply-To: <20170906082520.xgvo3hewje7jvdyo@hirez.programming.kicks-ass.net>



> On Sep 6, 2017, at 1:25 AM, Peter Zijlstra <peterz@infradead.org> wrote:
> 
>> On Tue, Sep 05, 2017 at 10:13:39PM -0700, Andy Lutomirski wrote:
>> I'm running e7d0c41ecc2e372a81741a30894f556afec24315 from Linus' tree
>> today, and I'm seeing abysmal scheduler performance.  Running make -j4
>> ends up with all the tasks on CPU 3 most of the time (on my
>> 4-logical-thread laptop).  taskset -c 0 whatever puts whatever on CPU
>> 0, but plain while true; do true; done puts the infinite loop on CPU 3
>> right along with the make -j4 tasks.
>> 
>> This is on Fedora 26, and I don't think I'm doing anything weird.
>> systemd has enabled the cpu controller, but it doesn't seem to have
>> configured anything or created any non-root cgroups.
>> 
>> Just a heads up.  I haven't tried to diagnose it at all.
> 
> "make O=defconfig-build -j80" results in:
> 
> %Cpu0  : 90.7 us,  9.3 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu1  : 88.7 us, 11.3 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu2  : 93.5 us,  6.5 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu3  : 86.8 us, 13.2 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu4  : 89.7 us, 10.3 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu5  : 96.3 us,  3.7 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu6  : 95.3 us,  4.7 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu7  : 94.4 us,  5.6 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu8  : 91.7 us,  8.3 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu9  : 94.3 us,  5.7 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu10 : 90.7 us,  9.3 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu11 : 96.2 us,  3.8 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu12 : 91.5 us,  8.5 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu13 : 90.6 us,  9.4 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu14 : 97.2 us,  2.8 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu15 : 89.7 us, 10.3 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu16 : 90.6 us,  9.4 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu17 : 93.4 us,  6.6 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu18 : 90.6 us,  9.4 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu19 : 92.5 us,  7.5 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu20 : 94.4 us,  5.6 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu21 : 90.7 us,  9.3 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu22 : 92.5 us,  7.5 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu23 : 90.7 us,  9.3 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu24 : 91.6 us,  8.4 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu25 : 93.5 us,  6.5 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu26 : 93.4 us,  5.7 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.9 si,  0.0 st
> %Cpu27 : 92.5 us,  7.5 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu28 : 92.5 us,  7.5 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu29 : 88.8 us, 11.2 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu30 : 90.6 us,  9.4 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu31 : 93.5 us,  6.5 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu32 : 93.5 us,  6.5 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu33 : 93.4 us,  6.6 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu34 : 90.7 us,  9.3 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu35 : 93.5 us,  6.5 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu36 : 90.7 us,  9.3 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu37 : 97.2 us,  2.8 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu38 : 92.5 us,  7.5 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> %Cpu39 : 92.6 us,  7.4 sy,  0.0 ni,  0.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
> 
> Do you have a .config somewhere?

I'll attach tomorrow.  I'll also test in a VM.

> Are you running with the systemd? Is it
> creating cpu cgroups?

Yes systemd, no cgroups.

> 
> Any specifics on your setup?

On further fiddling, I only see this after a suspend and resume cycle.

  reply index

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-06  5:13 Andy Lutomirski
2017-09-06  8:25 ` Peter Zijlstra
2017-09-06  8:59   ` Andy Lutomirski [this message]
2017-09-06  9:03     ` Peter Zijlstra
2017-09-06 16:14       ` Peter Zijlstra
2017-09-07  6:15         ` Mike Galbraith
2017-09-07  7:31           ` Ingo Molnar
2017-09-07  9:13           ` [PATCH] sched/cpuset/pm: Fix cpuset vs suspend-resume Peter Zijlstra
2017-09-07  9:26             ` Peter Zijlstra
2017-09-07 10:54               ` Rafael J. Wysocki
2017-09-07 20:38               ` Tejun Heo
2017-09-07 10:33             ` [tip:sched/urgent] sched/cpuset/pm: Fix cpuset vs. suspend-resume bugs tip-bot for Peter Zijlstra
2017-09-06  9:15 ` Abysmal scheduler performance in Linus' tree? Chris Wilson
2017-09-06  9:24   ` Peter Zijlstra
     [not found]     ` <150469312649.28581.17626550155735691534@mail.alporthouse.com>
2017-09-06 10:44       ` Peter Zijlstra
2017-09-06 10:51         ` Peter Zijlstra
2017-09-07  8:16           ` [tip:sched/urgent] sched/fair: Fix wake_affine_llc() balancing rules tip-bot for Peter Zijlstra

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