From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Doug Smythies" Subject: RE: Ask for help on governor Date: Tue, 12 Dec 2017 08:18:19 -0800 Message-ID: <000801d37364$d48f6ed0$7dae4c70$@net> References: Of1qe6hVbC2CsOf1seMkbL Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from cmta18.telus.net ([209.171.16.91]:36316 "EHLO cmta18.telus.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750853AbdLLQSY (ORCPT ); Tue, 12 Dec 2017 11:18:24 -0500 In-Reply-To: Of1qe6hVbC2CsOf1seMkbL Content-Language: en-ca Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: 'Viresh Kumar' , 'Andy Tang' Cc: rjw@rjwysocki.net, linux-pm@vger.kernel.org On 2017.12.11 23:31 Viresh Kumar wrote: > On 12-12-17, 02:46, Andy Tang wrote: >> Hi, >> >> I run into a question that conservative governor can't work while ondemand governor works well. >> When cpu load gets higher, if ondemand governor is used, cpu frequency can get higher and higher. >> But if I use conservative governor, cpu frequency stays on lowest frequency no matter what cpu load is. >> >> This issue was found on kernel 4.14.0, on kernel 4.9 kernel. It acts well. > > You mean to say that the problem exists on 4.14 but not on 4.9? > > Strange, as we haven't seen any such reports from anyone else. Well, it is easy enough for us to check. Indeed, it is broken in kernel 4.14-rc1, but O.K. in kernel 4.13. It remains broken in kernel 4.15-rc1 (I am not on -rc3 yet). Because it was easier for me to do so, I used intel_cpufreq (i.e. intel_pstate in passive mode). > >> I think it may related to cpufreq framework, not driver itself. Could you guys give me some clues on how to debug it? >> I don't expect a direct answer; any suggestions are welcome. > > Please provide output of below: > > grep . /sys/devices/system/cpu/cpufreq/policy*/* > > And then you may need to bisect the problem as well by going to kernel version > in between 4.9 and 4.14. @Andy: Have you started bisecting the kernel yet? I suppose I could if you haven't, or if you do not know how. ... Doug