From: Mike Galbraith <umgwanakikbuti@gmail.com>
To: Rik van Riel <riel@redhat.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
linaro-kernel@lists.linaro.org
Subject: Re: [PATCH RFC] sched,idle: teach select_idle_sibling about idle states
Date: Fri, 03 Oct 2014 08:04:23 +0200 [thread overview]
Message-ID: <1412316263.5149.9.camel@marge.simpson.net> (raw)
In-Reply-To: <20141002131548.6cd377d5@cuia.bos.redhat.com>
On Thu, 2014-10-02 at 13:15 -0400, Rik van Riel wrote:
> This patch is ugly. I have not bothered cleaning it up, because it
> causes a regression with hackbench. Apparently for hackbench (and
> potentially other sync wakeups), locality is more important than
> idleness.
>
> We may need to add a third clause before the search, something
> along the lines of, to ensure target gets selected if neither
> target or i are idle and the wakeup is synchronous...
>
> if (sync_wakeup && cpu_of(target)->nr_running == 1)
> return target;
I recommend you forget that trusting sync hint ever sprang to mind, it
is often a big fat lie.
-Mike
next prev parent reply other threads:[~2014-10-03 6:04 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-04 15:32 [PATCH v2 0/2] sched/idle : find the best idle CPU with cpuidle info Nicolas Pitre
2014-09-04 15:32 ` [PATCH v2 1/2] sched: let the scheduler see CPU idle states Nicolas Pitre
2014-09-18 17:37 ` Paul E. McKenney
2014-09-18 17:39 ` Paul E. McKenney
2014-09-18 23:15 ` Peter Zijlstra
2014-09-18 18:32 ` Nicolas Pitre
2014-09-18 23:17 ` Peter Zijlstra
2014-09-18 23:28 ` Peter Zijlstra
2014-09-19 18:30 ` Nicolas Pitre
2014-09-04 15:32 ` [PATCH v2 2/2] sched/fair: leverage the idle state info when choosing the "idlest" cpu Nicolas Pitre
2014-09-05 7:52 ` Daniel Lezcano
2014-09-18 23:46 ` Peter Zijlstra
2014-09-19 0:05 ` Peter Zijlstra
2014-09-19 4:49 ` Yao Dongdong
2014-09-30 21:58 ` Rik van Riel
2014-09-30 23:15 ` Nicolas Pitre
2014-10-02 17:15 ` [PATCH RFC] sched,idle: teach select_idle_sibling about idle states Rik van Riel
2014-10-03 6:04 ` Mike Galbraith [this message]
2014-10-03 6:23 ` Mike Galbraith
2014-10-03 7:50 ` Peter Zijlstra
2014-10-03 13:05 ` Mike Galbraith
2014-10-03 14:28 ` Rik van Riel
2014-10-03 14:46 ` Peter Zijlstra
2014-10-03 15:37 ` Rik van Riel
2014-10-09 16:04 ` Peter Zijlstra
2014-10-03 18:52 ` Nicolas Pitre
2014-09-10 21:35 ` [PATCH v2 0/2] sched/idle : find the best idle CPU with cpuidle info Nicolas Pitre
2014-09-10 22:50 ` Rafael J. Wysocki
2014-09-10 23:25 ` Nicolas Pitre
2014-09-10 23:28 ` Nicolas Pitre
2014-09-10 23:50 ` Rafael J. Wysocki
2014-09-18 0:39 ` Nicolas Pitre
2014-09-18 23:24 ` Peter Zijlstra
2014-09-19 18:22 ` Nicolas Pitre
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