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From: Peter Zijlstra <peterz@infradead.org>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Zhang Qiao <zhangqiao22@huawei.com>,
	linux-kernel@vger.kernel.org, mingo@redhat.com,
	juri.lelli@redhat.com, dietmar.eggemann@arm.com,
	rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
	bristot@redhat.com, vschneid@redhat.com, rkagan@amazon.de
Subject: Re: [PATCH v2] sched/fair: sanitize vruntime of entity being migrated
Date: Thu, 9 Mar 2023 15:36:56 +0100	[thread overview]
Message-ID: <ZAnvCGdlOrWbIC/o@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20230309142825.GB273121@hirez.programming.kicks-ass.net>

On Thu, Mar 09, 2023 at 03:28:25PM +0100, Peter Zijlstra wrote:
> On Thu, Mar 09, 2023 at 02:34:05PM +0100, Vincent Guittot wrote:
> 
> > Then, even if we don't clear exec_start before migrating and keep
> > current value to be used in place_entity on the new cpu, we can't
> > compare the rq_clock_task(rq_of(cfs_rq)) of 2 different rqs AFAICT
> 
> Blergh -- indeed, irq and steal time can skew them between CPUs :/
> I suppose we can fudge that... wait_start (which is basically what we're
> making it do) also does that IIRC.
> 
> I really dislike having this placement muck spreadout like proposed.

Also, I think we might be over-engineering this, we don't care about
accuracy at all, all we really care about is 'long-time'.



  reply	other threads:[~2023-03-09 14:38 UTC|newest]

Thread overview: 59+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-06 13:24 [PATCH v2] sched/fair: sanitize vruntime of entity being migrated Zhang Qiao
2023-03-06 13:53 ` Vincent Guittot
2023-03-07 10:26   ` Vincent Guittot
2023-03-07 11:05     ` Zhang Qiao
2023-03-07 13:41     ` Zhang Qiao
2023-03-08  8:01       ` Vincent Guittot
2023-03-08 12:55         ` Vincent Guittot
2023-03-09  8:37           ` Zhang Qiao
2023-03-09  9:09             ` Dietmar Eggemann
2023-03-09  9:30               ` Zhang Qiao
2023-03-09 10:48             ` Vincent Guittot
2023-03-09 14:23               ` Zhang Qiao
2023-03-07  2:16 ` kernel test robot
2023-03-07 12:45 ` Dietmar Eggemann
2023-03-07 14:06   ` Zhang Qiao
2023-03-09  9:43   ` Zhang Qiao
2023-03-08 14:33 ` Chen Yu
2023-03-09 13:05 ` Peter Zijlstra
2023-03-09 13:34   ` Vincent Guittot
2023-03-09 14:28     ` Peter Zijlstra
2023-03-09 14:36       ` Peter Zijlstra [this message]
2023-03-09 15:14         ` Vincent Guittot
2023-03-10 14:29           ` Vincent Guittot
2023-03-11  9:57             ` Zhang Qiao
2023-03-13 14:23               ` Vincent Guittot
2023-03-14 11:03                 ` Zhang Qiao
2023-03-14 13:26                   ` Vincent Guittot
2023-03-14 13:38                     ` Zhang Qiao
2023-03-14 13:39                       ` Vincent Guittot
2023-03-14 15:32                         ` Vincent Guittot
2023-03-15  9:16                           ` Zhang Qiao
2023-03-15 15:30                             ` Vincent Guittot
2023-03-13  9:06             ` Dietmar Eggemann
2023-03-13 18:17               ` Dietmar Eggemann
2023-03-14  7:41                 ` Vincent Guittot
2023-03-14 12:07                   ` Peter Zijlstra
2023-03-14 13:24                     ` Vincent Guittot
2023-03-14 17:16                       ` Peter Zijlstra
2023-03-15  7:18                         ` Vincent Guittot
2023-03-15  8:42                           ` Vincent Guittot
2023-03-15 10:15                             ` Dietmar Eggemann
2023-03-15 10:21                               ` Vincent Guittot
2023-03-15 13:35                                 ` Dietmar Eggemann
2023-03-15 15:32                                   ` Vincent Guittot
2023-03-14 13:29                     ` Dietmar Eggemann
2023-03-14 13:37                       ` Dietmar Eggemann
  -- strict thread matches above, loose matches on Subject: below --
2023-03-17 16:08 Vincent Guittot
2023-03-18  7:45 ` Zhang Qiao
2023-03-20 12:29   ` Dietmar Eggemann
2023-03-20 13:26     ` Vincent Guittot
2023-03-21 10:02 ` Peter Zijlstra
2023-03-21 10:29   ` Dietmar Eggemann
2023-03-21 10:49     ` Peter Zijlstra
2023-03-21 11:12       ` Vincent Guittot
2023-03-21 11:13       ` Dietmar Eggemann
2023-03-21 12:26         ` Peter Zijlstra
2023-03-21 12:28 ` Peter Zijlstra
2023-03-21 12:38   ` Vincent Guittot
2023-03-24  4:05 ` Chen Yu

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