From: Peng Liu <iwtbavbm@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, mingo@redhat.com,
dietmar.eggemann@arm.com, juri.lelli@redhat.com,
vincent.guittot@linaro.org, rostedt@goodmis.org,
bsegall@google.com, mgorman@suse.de, qais.yousef@arm.com,
morten.rasmussen@arm.com, valentin.schneider@arm.com
Subject: Re: [PATCH v2] sched/fair: fix sgc->{min,max}_capacity miscalculate
Date: Mon, 6 Jan 2020 22:52:27 +0800 [thread overview]
Message-ID: <20200106145227.GB15532@iZj6chx1xj0e0buvshuecpZ> (raw)
In-Reply-To: <20200106102341.GM2810@hirez.programming.kicks-ass.net>
On Mon, Jan 06, 2020 at 11:23:41AM +0100, Peter Zijlstra wrote:
> On Sat, Jan 04, 2020 at 09:08:28PM +0800, Peng Liu wrote:
> > commit bf475ce0a3dd ("sched/fair: Add per-CPU min capacity to
> > sched_group_capacity") introduced per-cpu min_capacity.
> >
> > commit e3d6d0cb66f2 ("sched/fair: Add sched_group per-CPU max capacity")
> > introduced per-cpu max_capacity.
> >
> > Here, capacity is the accumulated sum of (maybe) many CPUs' capacity.
> > Compare with capacity to get {min,max}_capacity makes no sense. Instead,
> > we should compare one by one in each iteration to get
> > sgc->{min,max}_capacity of the group.
> >
> > Also, the only CPU in rq->sd->groups should be rq's CPU. Thus,
> > capacity_of(cpu_of(rq)) should be equal to rq->sd->groups->sgc->capacity.
> > Code can be simplified by removing the if/else.
> >
> > Signed-off-by: Peng Liu <iwtbavbm@gmail.com>
> > Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
> > ---
> > v1: https://lkml.org/lkml/2019/12/30/502
>
> Please (for future use); use the form:
>
> https://lkml.kernel.org/r/$msgid
Peter, thanks, I will.
>
next prev parent reply other threads:[~2020-01-06 14:52 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-04 13:08 [PATCH v2] sched/fair: fix sgc->{min,max}_capacity miscalculate Peng Liu
2020-01-06 9:25 ` Dietmar Eggemann
2020-01-06 10:28 ` Peter Zijlstra
2020-01-06 14:49 ` Peng Liu
2020-01-06 10:23 ` Peter Zijlstra
2020-01-06 14:52 ` Peng Liu [this message]
2020-01-17 10:08 ` [tip: sched/core] sched/fair: Fix sgc->{min,max}_capacity calculation for SD_OVERLAP tip-bot2 for Peng Liu
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