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From: Frederic Weisbecker <frederic@kernel.org>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	linux-kernel@vger.kernel.org,
	Nitesh Narayan Lal <nitesh@redhat.com>,
	Peter Xu <peterx@redhat.com>
Subject: Re: [patch 1/2] nohz: only wakeup a single target cpu when kicking a task
Date: Thu, 22 Oct 2020 14:53:55 +0200	[thread overview]
Message-ID: <20201022125355.GA16049@lothringen> (raw)
In-Reply-To: <20201020185245.GA3577@fuller.cnet>

On Tue, Oct 20, 2020 at 03:52:45PM -0300, Marcelo Tosatti wrote:
> On Thu, Oct 15, 2020 at 01:40:53AM +0200, Frederic Weisbecker wrote:
> > Alternatively, we could rely on p->on_rq which is set to TASK_ON_RQ_QUEUED
> > at wake up time, prior to the schedule() full barrier. Of course that doesn't
> > mean that the task is actually the one running on the CPU but it's a good sign,
> > considering that we are running in nohz_full mode and it's usually optimized
> > for single task mode.
> 
> Unfortunately that would require exporting p->on_rq which is internal to
> the scheduler, locklessly.
> 
> (can surely do that if you prefer!)

May be:

    bool task_on_rq(struct task_struct *p) ?

Thanks.

  reply	other threads:[~2020-10-22 12:54 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-07 18:01 [patch 0/2] nohz_full: only wakeup target CPUs when notifying new tick dependency (v2) Marcelo Tosatti
2020-10-07 18:01 ` [patch 1/2] nohz: only wakeup a single target cpu when kicking a task Marcelo Tosatti
2020-10-08 12:22   ` Peter Zijlstra
2020-10-08 17:54     ` Marcelo Tosatti
2020-10-08 19:54       ` Frederic Weisbecker
2020-10-13 17:13         ` Marcelo Tosatti
2020-10-14  8:33           ` Peter Zijlstra
2020-10-14 23:40             ` Frederic Weisbecker
2020-10-15 10:12               ` Peter Zijlstra
2020-10-26 14:42                 ` Frederic Weisbecker
2020-10-20 18:52               ` Marcelo Tosatti
2020-10-22 12:53                 ` Frederic Weisbecker [this message]
2020-10-08 14:59   ` Peter Xu
2020-10-08 15:28     ` Peter Zijlstra
2020-10-08 19:16       ` Peter Xu
2020-10-08 19:48       ` Frederic Weisbecker
2020-10-08 17:43     ` Marcelo Tosatti
2020-10-07 18:01 ` [patch 2/2] nohz: change signal tick dependency to wakeup CPUs of member tasks Marcelo Tosatti
2020-10-08 12:35   ` Peter Zijlstra
2020-10-08 18:04     ` Marcelo Tosatti
2020-10-08 19:11 [patch 0/2] nohz_full: only wakeup target CPUs when notifying new tick dependency (v3) Marcelo Tosatti
2020-10-08 19:11 ` [patch 1/2] nohz: only wakeup a single target cpu when kicking a task Marcelo Tosatti

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