From: Mike Galbraith <efault@gmx.de>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Michael Wang <wangyun@linux.vnet.ibm.com>,
LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH] sched: remove useless code in yield_to
Date: Thu, 12 Jul 2012 20:44:51 +0200 [thread overview]
Message-ID: <1342118691.7430.39.camel@marge.simpson.net> (raw)
In-Reply-To: <1342102029.28010.3.camel@twins>
On Thu, 2012-07-12 at 16:07 +0200, Peter Zijlstra wrote:
> On Tue, 2012-07-03 at 14:34 +0800, Michael Wang wrote:
> > From: Michael Wang <wangyun@linux.vnet.ibm.com>
> >
> > it's impossible to enter else branch if we have set skip_clock_update
> > in task_yield_fair(), as yield_to_task_fair() will directly return
> > true after invoke task_yield_fair().
>
> It helps if you CC the guy who wrote the code.. I think you're right,
> although getting that skip_clock_update crap wrong is annoying.
Getting that crap wrong is ease, so Michael is probably right.
> Mike?
If it looks right to you too, it likely is. When I have time to look
for nanoseconds again, I can squeak if/when I find some. In any case,
for normal scheduler citizens, it's chump change, so nuke it.
> > Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com>
> > ---
> > kernel/sched/core.c | 7 -------
> > 1 files changed, 0 insertions(+), 7 deletions(-)
> >
> > diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> > index 9bb7d28..77c14aa 100644
> > --- a/kernel/sched/core.c
> > +++ b/kernel/sched/core.c
> > @@ -4737,13 +4737,6 @@ again:
> > */
> > if (preempt && rq != p_rq)
> > resched_task(p_rq->curr);
> > - } else {
> > - /*
> > - * We might have set it in task_yield_fair(), but are
> > - * not going to schedule(), so don't want to skip
> > - * the next update.
> > - */
> > - rq->skip_clock_update = 0;
> > }
> >
> > out:
>
> --
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next prev parent reply other threads:[~2012-07-12 18:44 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-16 9:37 [PATCH] sched: Accelerate "pick_next_entity" under special condition Michael Wang
2012-01-16 9:50 ` Michael Wang
2012-01-16 9:51 ` Peter Zijlstra
2012-01-16 10:34 ` Michael Wang
2012-01-17 2:36 ` [PATCH v2] " Michael Wang
2012-01-17 2:41 ` Michael Wang
2012-01-17 2:58 ` Xiaotian Feng
2012-01-17 3:04 ` Michael Wang
2012-01-25 15:55 ` Peter Zijlstra
2012-01-26 10:04 ` Ingo Molnar
2012-01-27 1:22 ` Michael Wang
2012-01-27 4:42 ` Cong Wang
2012-01-29 6:32 ` Michael Wang
2012-01-29 16:33 ` Ingo Molnar
2012-01-30 3:18 ` Michael Wang
2012-01-30 3:25 ` Cong Wang
2012-01-30 5:47 ` Michael Wang
2012-07-03 6:34 ` [PATCH] sched: remove useless code in yield_to Michael Wang
2012-07-12 5:45 ` Michael Wang
2012-07-12 14:07 ` Peter Zijlstra
2012-07-12 18:44 ` Mike Galbraith [this message]
2012-07-16 2:39 ` Michael Wang
2012-08-17 6:56 ` Michael Wang
2012-08-17 9:43 ` Peter Zijlstra
2012-08-10 3:05 ` Michael Wang
2012-08-10 3:10 ` Michael Wang
2012-08-10 5:52 ` Mike Galbraith
2012-09-04 18:50 ` [tip:sched/core] sched: Remove useless code in yield_to() tip-bot for Michael Wang
2012-01-27 0:56 ` [PATCH v2] sched: Accelerate "pick_next_entity" under special condition Michael Wang
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