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From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Mel Gorman <mgorman@techsingularity.net>,
	Rik van Riel <riel@surriel.com>, Yi Wang <wang.yi59@zte.com.cn>,
	zhong.weidong@zte.com.cn, Yi Liu <liu.yi24@zte.com.cn>,
	Frederic Weisbecker <frederic@kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v2] sched/core: Don't mix isolcpus and housekeeping CPUs
Date: Fri, 26 Oct 2018 15:00:55 +0530	[thread overview]
Message-ID: <20181026093055.GF18466@linux.vnet.ibm.com> (raw)
In-Reply-To: <20181026084105.GY3109@worktop.c.hoisthospitality.com>

* Peter Zijlstra <peterz@infradead.org> [2018-10-26 10:41:05]:

> > #
> > # ./hist.sh
> > 10:35:21  IST   UID      TGID       TID    %usr %system  %guest    %CPU   CPU  Command
> > 10:35:21  IST     0      2645         -    8.70    0.01    0.00    8.71     1  ebizzy
> > 10:35:21  IST     0         -      2645    0.01    0.00    0.00    0.01     1  |__ebizzy
> > 10:35:21  IST     0         -      2647    0.14    0.00    0.00    0.14     1  |__ebizzy
> > 10:35:21  IST     0         -      2648    0.13    0.00    0.00    0.13     1  |__ebizzy
> > 10:35:21  IST     0         -      2649    0.13    0.00    0.00    0.13     1  |__ebizzy
> > 10:35:21  IST     0         -      2650    0.13    0.00    0.00    0.13     1  |__ebizzy
> > 10:35:21  IST     0         -      2651    0.13    0.00    0.00    0.13     1  |__ebizzy
> > 10:35:21  IST     0         -      2652    0.13    0.00    0.00    0.13     1  |__ebizzy
> > 10:35:21  IST     0         -      2653    0.13    0.00    0.00    0.13     1  |__ebizzy
> > 10:35:23  IST   UID      TGID       TID    %usr %system  %guest    %CPU   CPU  Command
> > 10:35:23  IST     0      2642         -    0.00    0.00    0.00    0.00     1  hist.sh
> > 10:35:23  IST     0         -      2642    0.00    0.00    0.00    0.00     1  |__hist.sh
> > #
> 
> That's correct and specified behaviour.
> 
> cpu1 has no sched domain (or the singleton domaon, which is the same)
> and thus its tasks will not be migrated.
> 

As I mentioned, If every run was the same, then it would have been good.
However if we increase the cpuset from 1-8 to 1-31 then we seen spreading
more often but not always.

./hist.sh
02:59:10  IST   UID      TGID       TID    %usr %system  %guest    %CPU   CPU  Command
02:59:10  IST     0      2244         -  100.00    0.13    0.00  100.00    30  ebizzy
02:59:10  IST     0         -      2244    0.00    0.02    0.00    0.02    30  |__ebizzy
02:59:10  IST     0         -      2246    4.37    0.00    0.00    4.37    21  |__ebizzy
02:59:10  IST     0         -      2247    2.14    0.00    0.00    2.14     8  |__ebizzy
02:59:10  IST     0         -      2248    3.13    0.00    0.00    3.13    28  |__ebizzy
02:59:10  IST     0         -      2249    5.57    0.00    0.00    5.57    18  |__ebizzy
02:59:10  IST     0         -      2250    4.29    0.00    0.00    4.29    11  |__ebizzy
02:59:10  IST     0         -      2251    5.32    0.00    0.00    5.32    19  |__ebizzy
02:59:10  IST     0         -      2252    5.62    0.00    0.00    5.62    17  |__ebizzy
02:59:11  IST   UID      TGID       TID    %usr %system  %guest    %CPU   CPU  Command
02:59:11  IST     0      2241         -    0.00    0.00    0.00    0.00    29  hist.sh
02:59:11  IST     0         -      2241    0.00    0.00    0.00    0.00    29  |__hist.sh


> If there is a problem, it is with cpuset and its interaction with
> isolcpus. I still have to look at the last version of cpuset-v2, but
> iirc that was better in this regard.

Okay.

-- 
Thanks and Regards
Srikar Dronamraju


  reply	other threads:[~2018-10-26  9:31 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-24  3:02 [PATCH v2] sched/core: Don't mix isolcpus and housekeeping CPUs Srikar Dronamraju
2018-10-24  8:56 ` Mel Gorman
2018-10-24  9:46   ` Srikar Dronamraju
2018-10-24 10:15     ` Peter Zijlstra
2018-10-24 10:41       ` Srikar Dronamraju
2018-10-24 11:21         ` Mel Gorman
2018-10-24 10:31     ` Mel Gorman
2018-10-24 10:03 ` Peter Zijlstra
2018-10-24 10:30   ` Srikar Dronamraju
2018-10-25  0:07     ` Peter Zijlstra
2018-10-25 17:30       ` Srikar Dronamraju
2018-10-26  8:41         ` Peter Zijlstra
2018-10-26  9:30           ` Srikar Dronamraju [this message]
2018-10-25 18:23       ` Srikar Dronamraju
2018-10-26  8:42         ` Peter Zijlstra

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