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From: Josh Don <joshdon@google.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Tao Zhou <tao.zhou@linux.dev>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Joel Fernandes <joel@joelfernandes.org>,
	"Hyser,Chris" <chris.hyser@oracle.com>,
	Ingo Molnar <mingo@kernel.org>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Valentin Schneider <valentin.schneider@arm.com>,
	Mel Gorman <mgorman@suse.de>
Subject: Re: [PATCH] sched/core: An optimization of pick_next_task() not sure
Date: Mon, 16 Aug 2021 12:02:34 -0700	[thread overview]
Message-ID: <CABk29Nt=a0RPfoVMP=FiKY_ObtU9enYU3cK00RgDUVqJrTmkiQ@mail.gmail.com> (raw)
In-Reply-To: <YRqz93crZIS1Mvmy@hirez.programming.kicks-ass.net>

On Mon, Aug 16, 2021 at 11:53 AM Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Mon, Aug 16, 2021 at 11:44:01PM +0800, Tao Zhou wrote:
> > When find a new candidate max, wipe the stale and start over.
> > Goto again: and use the new max to loop to pick the the task.
> >
> > Here first want to get the max of the core and use this new
> > max to loop once to pick the task on each thread.
> >
> > Not sure this is an optimization and just stop here a little
> > and move on..
> >
>
> Did you find this retry was an issue on your workload? Or was this from
> reading the source?

I would be surprised if this made a noticeable difference on SMT2, but
I could certainly see how this would help with larger SMT
configurations where we have more opportunities to invalidate the
other siblings.

  reply	other threads:[~2021-08-16 19:02 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-16 15:44 Tao Zhou
2021-08-16 18:52 ` Peter Zijlstra
2021-08-16 19:02   ` Josh Don [this message]
2021-08-17 16:45   ` Tao Zhou
2021-08-18 19:23     ` Tao Zhou

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