From: Peter Zijlstra <peterz@infradead.org>
To: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: linux-kernel@vger.kernel.org, Rik van Riel <riel@redhat.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
Oleg Nesterov <oleg@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH] sched/cputime: fix clock_nanosleep/clock_gettime inconsistency
Date: Wed, 12 Nov 2014 13:52:50 +0100 [thread overview]
Message-ID: <20141112125250.GC21343@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20141112122745.GB3250@redhat.com>
On Wed, Nov 12, 2014 at 01:27:53PM +0100, Stanislaw Gruszka wrote:
> On Wed, Nov 12, 2014 at 12:45:38PM +0100, Peter Zijlstra wrote:
> > On Wed, Nov 12, 2014 at 12:37:37PM +0100, Peter Zijlstra wrote:
> >
> > > Which would make the sample run ahead, making the sleep short. So would
> > > something like the below not cure things?
> >
> > Before anyone asks, yes I tried running that 'reproducer' it doesn't.
>
> I'd be surprised if the patch would help. Issue here happen at start of
> cputimer. We set sum_sched_runtime value of cputimer using not yet
> accounted threads runtime and then add that runtime values again to
> running cputimer on tick, making it's sum_exec_runtime bigger than
> actual threads runtime.
Ah yes, reading is hard.
next prev parent reply other threads:[~2014-11-12 12:52 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-12 10:29 [PATCH] sched/cputime: fix clock_nanosleep/clock_gettime inconsistency Stanislaw Gruszka
2014-11-12 11:15 ` Peter Zijlstra
2014-11-12 11:37 ` Peter Zijlstra
2014-11-12 11:45 ` Peter Zijlstra
2014-11-12 12:27 ` Stanislaw Gruszka
2014-11-12 12:52 ` Peter Zijlstra [this message]
2014-11-16 9:50 ` [tip:sched/urgent] sched/cputime: Fix cpu_timer_sample_group() double accounting tip-bot for Peter Zijlstra
2014-11-12 12:21 ` [PATCH] sched/cputime: fix clock_nanosleep/clock_gettime inconsistency Stanislaw Gruszka
2014-11-12 12:51 ` Peter Zijlstra
2014-11-12 15:58 ` [PATCH v2] " Stanislaw Gruszka
2014-11-12 16:06 ` Peter Zijlstra
2014-11-12 16:17 ` Stanislaw Gruszka
2014-11-12 17:12 ` Peter Zijlstra
2014-11-12 16:45 ` Peter Zijlstra
2014-11-12 16:53 ` Stanislaw Gruszka
2014-11-12 16:56 ` Peter Zijlstra
2014-11-16 9:50 ` [tip:sched/urgent] sched/cputime: Fix clock_nanosleep()/ clock_gettime() inconsistency tip-bot for Stanislaw Gruszka
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