From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Shi Subject: Re: [PATCH RFC v2 4/4] sched: cpufreq_cfs: pelt-based cpu frequency scaling Date: Wed, 10 Jun 2015 14:23:23 +0800 Message-ID: <5577D7DB.5020802@linaro.org> References: <1431396795-32439-1-git-send-email-mturquette@linaro.org> <1431396795-32439-5-git-send-email-mturquette@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-qk0-f177.google.com ([209.85.220.177]:35947 "EHLO mail-qk0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933178AbbFJGXc (ORCPT ); Wed, 10 Jun 2015 02:23:32 -0400 Received: by qkx62 with SMTP id 62so20439049qkx.3 for ; Tue, 09 Jun 2015 23:23:31 -0700 (PDT) In-Reply-To: <1431396795-32439-5-git-send-email-mturquette@linaro.org> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Michael Turquette , peterz@infradead.org, mingo@kernel.org Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, preeti@linux.vnet.ibm.com, Morten.Rasmussen@arm.com, riel@redhat.com, efault@gmx.de, nicolas.pitre@linaro.org, daniel.lezcano@linaro.org, dietmar.eggemann@arm.com, vincent.guittot@linaro.org, amit.kucheria@linaro.org, juri.lelli@arm.com, rjw@rjwysocki.net, viresh.kumar@linaro.org, ashwin.chaugule@linaro.org, abelvesa@gmail.com On 05/12/2015 10:13 AM, Michael Turquette wrote: > This governor is event-driven. There is no polling loop to check cpu > idle time nor any other method which is unsynchronized with the > scheduler. The entry points for this policy are in fair.c: > enqueue_task_fair, dequeue_task_fair and task_tick_fair. > > This policy is implemented using the cpufreq governor interface for two > main reasons: > > 1) re-using the cpufreq machine drivers without using the governor > interface is hard. > > 2) using the cpufreq interface allows us to switch between the > scheduler-driven policy and legacy cpufreq governors such as ondemand at > run-time. This is very useful for comparative testing and tuning. Hi, Mike, Did you have some testing data with your patch?