From: Peter Zijlstra <peterz@infradead.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: "pang.xunlei" <pang.xunlei@linaro.org>,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
Juri Lelli <juri.lelli@gmail.com>
Subject: Re: [PATCH v2 5/6] sched/dl: Optimize select_task_rq_dl() for non-DL curr task
Date: Tue, 4 Nov 2014 16:11:09 +0100 [thread overview]
Message-ID: <20141104151109.GI10501@worktop.programming.kicks-ass.net> (raw)
In-Reply-To: <20141104094549.59acebb6@gandalf.local.home>
On Tue, Nov 04, 2014 at 09:45:49AM -0500, Steven Rostedt wrote:
> > +++ b/kernel/sched/deadline.c
> > @@ -954,6 +954,9 @@ select_task_rq_dl(struct task_struct *p, int cpu, int sd_flag, int flags)
> > struct task_struct *curr;
> > struct rq *rq;
> >
> > + if (p->nr_cpus_allowed == 1)
> > + goto out;
> > +
>
> This looks fine, and I'm wondering if we shouldn't just move this into
> kernel/sched/core.c: select_task_rq(). Why bother calling the select_rq
> code if the task is pinned?
>
> This change will make fair.c, rt.c, and deadline.c all start with the
> same logic. If this should be an optimization, just move it to core.c
> and be done with it.
Yeah, that makes sense. Back when, in the olden days, nr_cpus_allowed
was specific to the rt class, but we fixed that.
next prev parent reply other threads:[~2014-11-04 15:11 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-04 11:13 [PATCH v2 1/6] sched/cpupri: Deal with cpupri.pri_to_cpu[CPUPRI_IDLE] for idle cases pang.xunlei
2014-11-04 11:13 ` [PATCH v2 2/6] sched/rt: Optimize select_task_rq_rt() for non-RT curr task pang.xunlei
2014-11-04 12:52 ` Steven Rostedt
2014-11-04 14:29 ` pang.xunlei
2014-11-04 14:47 ` Steven Rostedt
2014-11-04 15:09 ` pang.xunlei
2014-11-04 11:13 ` [PATCH v2 3/6] sched/cpupri: Remove unnecessary definitions in cpupri.h pang.xunlei
2014-11-04 14:39 ` Steven Rostedt
2014-11-04 11:13 ` [PATCH v2 4/6] sched/dl: Modify cpudl_find() for more cases of electing best_cpu pang.xunlei
2014-11-04 11:13 ` [PATCH v2 5/6] sched/dl: Optimize select_task_rq_dl() for non-DL curr task pang.xunlei
2014-11-04 11:24 ` Wanpeng Li
2014-11-04 14:19 ` pang.xunlei
2014-11-04 23:30 ` Wanpeng Li
2014-11-04 14:45 ` Steven Rostedt
2014-11-04 15:11 ` Peter Zijlstra [this message]
2014-11-04 23:33 ` Wanpeng Li
2014-11-04 11:13 ` [PATCH v2 6/6] sched/dl: Remove unnecessary definitions in cpudeadline.h pang.xunlei
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