From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Prakash, Prashanth" Subject: Re: [PATCH] cpufreq: cpufreq_stats in the absence of frequency table Date: Wed, 3 Aug 2016 09:41:21 -0600 Message-ID: References: <1470179937-14698-1-git-send-email-pprakash@codeaurora.org> <1547887.jMFZtBx5tV@vostro.rjw.lan> <5a559b20-28f5-5b51-6b8e-11d7884709ab@codeaurora.org> <4103198.vv1olU1ZFT@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Return-path: Received: from smtp.codeaurora.org ([198.145.29.96]:60787 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751629AbcHCPli (ORCPT ); Wed, 3 Aug 2016 11:41:38 -0400 In-Reply-To: <4103198.vv1olU1ZFT@vostro.rjw.lan> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: "Rafael J. Wysocki" Cc: linux-pm@vger.kernel.org, viresh.kumar@linaro.org, alexey.klimov@arm.com, hotran@apm.com, cov@codeaurora.org Hi Rafael, On 8/2/2016 5:49 PM, Rafael J. Wysocki wrote: > On Tuesday, August 02, 2016 05:41:24 PM Prakash, Prashanth wrote: >> Hi Rafael, >> >> On 8/2/2016 5:27 PM, Rafael J. Wysocki wrote: >>> On Tuesday, August 02, 2016 05:18:57 PM Prashanth Prakash wrote: >>>> cpufreq drivers such as CPPC works on contigious scale and does >>>> not have a static frequency table. This commit adds cpufreq_stats >>>> support for such drivers by creating a pseudo frequency table by >>>> discretizing the contigious scale. >>> No. >>> >>> And why? >> The motivation is to be able to collect the frequency distribution data via >> time_in_state sysfs entry as we can collect for other cpufreq drivers that >> uses a frequency table. > Which can be done by using the cpu_frequency trace point just fine, can't it? Yes, but wanted to make sure existing userspace tools can be used with platforms using CPPC as well. > Plus, cpufreq_stats don't work with the schedutil governor and fast frequency > switching anyway. If we are expecting that usage of cpufreq_stats will slowly go away as we switch to schedutil and more drivers enable fast_switching, then I agree it doesn't make much sense to add support for cpufreq_stats. Thanks, Prashanth