From: Mike Galbraith <mgalbraith@suse.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: zhdxzx@sina.com, linux-kernel <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>, dhillf <dhillf@gmail.com>,
"hillf.zj" <hillf.zj@alibaba-inc.com>
Subject: Re: sched: how to pick runqueue when checking task hot?
Date: Fri, 06 Jun 2014 13:16:23 +0200 [thread overview]
Message-ID: <1402053383.5859.8.camel@marge.simpson.net> (raw)
In-Reply-To: <20140606101508.GP3213@twins.programming.kicks-ass.net>
On Fri, 2014-06-06 at 12:15 +0200, Peter Zijlstra wrote:
> > --- a/kernel/sched/fair.c Fri Jun 6 12:37:37 2014
> > +++ b/kernel/sched/fair.c Fri Jun 6 14:32:34 2014
> > @@ -5051,7 +5051,7 @@ task_hot(struct task_struct *p, u64 now)
> > /*
> > * Buddy candidates are cache hot:
> > */
> > - if (sched_feat(CACHE_HOT_BUDDY) && this_rq()->nr_running &&
> > + if (sched_feat(CACHE_HOT_BUDDY) && task_rq(p)->nr_running &&
> > (&p->se == cfs_rq_of(&p->se)->next ||
> > &p->se == cfs_rq_of(&p->se)->last))
> > return 1;
>
> That does appear to make more sense indeed, seeing how buddies are pairs
> of tasks, so protecting a lone task doesn't make sense.
>
>
> Mike, how did you intend this code to work?
IIRC, this_rq()->nr_running was to say if we're idle, we don't care that
it's last/next, pull it. Not sure I'm the one who did that, but could
be, I didn't look.
-Mike
next prev parent reply other threads:[~2014-06-06 11:16 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20140606065956.854A6718001@webmail.sinamail.sina.com.cn>
2014-06-06 10:15 ` sched: how to pick runqueue when checking task hot? Peter Zijlstra
2014-06-06 11:16 ` Mike Galbraith [this message]
2014-06-06 11:34 ` Peter Zijlstra
2014-06-06 11:50 ` Mike Galbraith
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