From: Yuyang Du <yuyang.du@intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: mingo@kernel.org, linux-kernel@vger.kernel.org,
bsegall@google.com, pjt@google.com, morten.rasmussen@arm.com,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com
Subject: Re: [PATCH v2 1/3] sched/fair: Clean up attach_entity_load_avg()
Date: Tue, 31 May 2016 08:49:54 +0800 [thread overview]
Message-ID: <20160531004954.GP18670@intel.com> (raw)
In-Reply-To: <20160531083402.GI3193@twins.programming.kicks-ass.net>
On Tue, May 31, 2016 at 10:34:02AM +0200, Peter Zijlstra wrote:
> On Tue, May 31, 2016 at 06:32:54AM +0800, Yuyang Du wrote:
> > +++ b/kernel/sched/fair.c
> > @@ -2961,24 +2961,6 @@ static inline void update_load_avg(struct sched_entity *se, int update_tg)
> >
> > static void attach_entity_load_avg(struct cfs_rq *cfs_rq, struct sched_entity *se)
> > {
> > - if (!sched_feat(ATTACH_AGE_LOAD))
> > - goto skip_aging;
> > -
> > - /*
> > - * If we got migrated (either between CPUs or between cgroups) we'll
> > - * have aged the average right before clearing @last_update_time.
> > - */
> > - if (se->avg.last_update_time) {
> > - __update_load_avg(cfs_rq->avg.last_update_time, cpu_of(rq_of(cfs_rq)),
> > - &se->avg, 0, 0, NULL);
> > -
> > - /*
> > - * XXX: we could have just aged the entire load away if we've been
> > - * absent from the fair class for too long.
> > - */
> > - }
> > -
> > -skip_aging:
> > se->avg.last_update_time = cfs_rq->avg.last_update_time;
> > cfs_rq->avg.load_avg += se->avg.load_avg;
> > cfs_rq->avg.load_sum += se->avg.load_sum;
>
> So I'm not a big fan of this patch; the aging is a conceptual part of
> attaching the load, the fact that it only happens in one callsite is a
> mere 'accident'.
Strictly in concept, it is part of load dealing, maybe not load attaching, :)
next prev parent reply other threads:[~2016-05-31 8:47 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-30 22:32 [PATCH v2 0/3] sched/fair: Skip attach and detach for new group task in task_move_group_fair() Yuyang Du
2016-05-30 22:32 ` [PATCH v2 1/3] sched/fair: Clean up attach_entity_load_avg() Yuyang Du
2016-05-31 8:34 ` Peter Zijlstra
2016-05-31 0:49 ` Yuyang Du [this message]
2016-05-31 9:14 ` Peter Zijlstra
2016-05-31 18:37 ` Yuyang Du
2016-05-30 22:32 ` [PATCH v2 2/3] sched/fair: Skip detach and attach new group task Yuyang Du
2016-05-31 11:55 ` Vincent Guittot
2016-05-31 12:03 ` Peter Zijlstra
2016-05-31 12:33 ` Vincent Guittot
2016-05-31 12:39 ` Peter Zijlstra
2016-05-31 13:20 ` Vincent Guittot
2016-05-30 22:32 ` [PATCH v2 3/3] sched/fair: Add inline to detach_entity_load_evg() Yuyang Du
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