From: Peter Zijlstra <peterz@infradead.org>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Yafang Shao <laoar.shao@gmail.com>,
Ingo Molnar <mingo@redhat.com>,
Juri Lelli <juri.lelli@redhat.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Benjamin Segall <bsegall@google.com>,
Mel Gorman <mgorman@suse.de>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
LKML <linux-kernel@vger.kernel.org>,
Valentin Schneider <valentin.schneider@arm.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH] sched, fair: try to prevent migration thread from preempting non-cfs task
Date: Wed, 16 Jun 2021 10:29:33 +0200 [thread overview]
Message-ID: <YMm2bWq9XfaPeSka@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CAKfTPtAh3eOtzZUPqmhkw6FAOjOietZrB_qMOfOprp0oWO+CvA@mail.gmail.com>
On Wed, Jun 16, 2021 at 09:29:55AM +0200, Vincent Guittot wrote:
> On Wed, 16 Jun 2021 at 09:15, Peter Zijlstra <peterz@infradead.org> wrote:
> > The suggestion was adding a cfs_migration thread, specifically for
> > active balance (and maybe numa). Just not sure the cost of carrying yet
> > another per-cpu kernel thread is worth the benefit.
>
> Also, this will not completely remove the problem but only further
> reduce the race window because the rq is locked and the irq disable in
> active_load_balance_cpu_stop().
It removes the problem of active migration interfering with this
worklaod, because the FIFO1 task will never run until that is done
(assuming he manages to not have his workload at FIFO1).
next prev parent reply other threads:[~2021-06-16 8:30 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-15 12:15 [PATCH] sched, fair: try to prevent migration thread from preempting non-cfs task Yafang Shao
2021-06-15 14:55 ` Valentin Schneider
2021-06-15 15:45 ` Vincent Guittot
2021-06-15 16:39 ` Valentin Schneider
2021-06-15 20:35 ` Peter Zijlstra
2021-06-16 1:44 ` Yafang Shao
2021-06-16 7:15 ` Peter Zijlstra
2021-06-16 7:29 ` Vincent Guittot
2021-06-16 8:29 ` Peter Zijlstra [this message]
2021-06-16 9:49 ` Yafang Shao
2021-06-16 9:45 ` Yafang Shao
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