From: Peter Zijlstra <peterz@infradead.org>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Chuansheng Liu <chuansheng.liu@intel.com>,
"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
"Wang, Xiaoming" <xiaoming.wang@intel.com>,
Ingo Molnar <mingo@redhat.com>,
"Chakravarty, Souvik K" <souvik.k.chakravarty@intel.com>,
"Liu, Changcheng" <changcheng.liu@intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/3] sched: Add new API wake_up_if_idle() to wake up the idle cpu
Date: Wed, 3 Sep 2014 11:54:10 +0200 [thread overview]
Message-ID: <20140903095410.GJ4783@worktop.ger.corp.intel.com> (raw)
In-Reply-To: <CALCETrWns2cPzS+goDmXjhVuxzD2OczxTF9UtARBFnw3hibjZg@mail.gmail.com>
On Thu, Aug 21, 2014 at 02:21:51PM -0700, Andy Lutomirski wrote:
> On Aug 18, 2014 3:52 AM, "Chuansheng Liu" <chuansheng.liu@intel.com> wrote:
> > +void wake_up_if_idle(int cpu)
> > +{
> > + struct rq *rq = cpu_rq(cpu);
> > + unsigned long flags;
> > +
> > + if (set_nr_if_polling(rq->idle)) {
> > + trace_sched_wake_idle_without_ipi(cpu);
> > + } else {
> > +
>
> FWIW, adding:
>
> if (rq->curr != rq->idle)
> return;
>
> Right here could improve performance on large, mostly non-idle
> systems. It would skip the spinlock in most cases.
>
!is_idle_task() :-)
next prev parent reply other threads:[~2014-09-03 9:54 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-18 8:37 [PATCH 1/3] sched: Add new API wake_up_if_idle() to wake up the idle cpu Chuansheng Liu
2014-08-18 8:37 ` [PATCH 2/3] smp: Adding new function wake_up_all_cpus() Chuansheng Liu
2014-09-03 9:52 ` Peter Zijlstra
2014-08-18 8:37 ` [PATCH 3/3] cpuidle: Using the wake_up_all_cpus() to wake up all idle cpus Chuansheng Liu
2014-08-21 1:54 ` [PATCH 1/3] sched: Add new API wake_up_if_idle() to wake up the idle cpu Daniel Lezcano
2014-08-21 2:12 ` Liu, Chuansheng
2014-08-21 3:48 ` Daniel Lezcano
2014-08-21 21:21 ` Andy Lutomirski
2014-09-03 9:54 ` Peter Zijlstra [this message]
2014-09-03 9:58 ` Liu, Chuansheng
2014-09-03 9:51 ` Peter Zijlstra
-- strict thread matches above, loose matches on Subject: below --
2014-09-04 7:17 Chuansheng Liu
2014-09-04 12:53 ` Daniel Lezcano
2014-09-04 12:59 ` Liu, Chuansheng
2014-08-15 7:01 Chuansheng Liu
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