From: "Liu, Chuansheng" <chuansheng.liu@intel.com>
To: Daniel Lezcano <daniel.lezcano@linaro.org>,
"peterz@infradead.org" <peterz@infradead.org>,
"luto@amacapital.net" <luto@amacapital.net>,
"rjw@rjwysocki.net" <rjw@rjwysocki.net>,
"mingo@redhat.com" <mingo@redhat.com>
Cc: "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Liu, Changcheng" <changcheng.liu@intel.com>,
"Wang, Xiaoming" <xiaoming.wang@intel.com>,
"Chakravarty, Souvik K" <souvik.k.chakravarty@intel.com>
Subject: RE: [PATCH 3/3] cpuidle: Using the wake_up_all_idle_cpus() to wake up all idle cpus
Date: Thu, 4 Sep 2014 13:39:38 +0000 [thread overview]
Message-ID: <27240C0AC20F114CBF8149A2696CBE4A01E6B3E3@SHSMSX101.ccr.corp.intel.com> (raw)
In-Reply-To: <540862AA.7060907@linaro.org>
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> -----Original Message-----
> From: Daniel Lezcano [mailto:daniel.lezcano@linaro.org]
> Sent: Thursday, September 04, 2014 9:02 PM
> To: Liu, Chuansheng; peterz@infradead.org; luto@amacapital.net;
> rjw@rjwysocki.net; mingo@redhat.com
> Cc: linux-pm@vger.kernel.org; linux-kernel@vger.kernel.org; Liu, Changcheng;
> Wang, Xiaoming; Chakravarty, Souvik K
> Subject: Re: [PATCH 3/3] cpuidle: Using the wake_up_all_idle_cpus() to wake up
> all idle cpus
>
> On 09/04/2014 09:17 AM, Chuansheng Liu wrote:
> > Currently kick_all_cpus_sync() or smp_call_function() can not
> > break the polling idle cpu immediately.
> >
> > Here using wake_up_all_idle_cpus() which can wake up the polling idle
> > cpu quickly is much helpful for power.
>
> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
>
> So IIUC, kick_all_cpus_sync is a broken function, right ?
>
> Wouldn't make sense to replace all calls to kick_all_cpus by
> wake_up_all_idle_cpus ? and remove this broken function ?
My initial patch(V1) indeed do it, but Andy pointed out some callers of kick_all_cpus_sync()
really want the old behavior.
My fault again that do not have the detailed changelog for the patches.
Pasted the comments from Andy:
==
> Currently using smp_call_function() just woke up the corresponding
> cpu, but can not break the polling idle loop.
>
> Here using the new sched API wake_up_if_idle() to implement it.
kick_all_cpus_sync has other callers, and those other callers want the
old behavior. I think this should be a new function.
--Andy
==
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next prev parent reply other threads:[~2014-09-04 13:51 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-04 7:17 [PATCH 1/3] sched: Add new API wake_up_if_idle() to wake up the idle cpu Chuansheng Liu
2014-09-04 7:17 ` [PATCH 2/3] smp: Adding new function wake_up_all_idle_cpus() Chuansheng Liu
2014-09-04 12:56 ` Daniel Lezcano
2014-09-19 11:44 ` [tip:sched/core] smp: Add new wake_up_all_idle_cpus() function tip-bot for Chuansheng Liu
2014-09-04 7:17 ` [PATCH 3/3] cpuidle: Using the wake_up_all_idle_cpus() to wake up all idle cpus Chuansheng Liu
2014-09-04 13:01 ` Daniel Lezcano
2014-09-04 13:39 ` Liu, Chuansheng [this message]
2014-09-04 15:47 ` Peter Zijlstra
2014-09-19 11:44 ` [tip:sched/core] cpuidle: Use " tip-bot for Chuansheng Liu
2014-09-04 12:53 ` [PATCH 1/3] sched: Add new API wake_up_if_idle() to wake up the idle cpu Daniel Lezcano
2014-09-04 12:59 ` Liu, Chuansheng
2014-09-19 11:43 ` [tip:sched/core] " tip-bot for Chuansheng Liu
2014-12-19 20:23 ` Andy Lutomirski
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