From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: [cpufreq-4.7] New schedutil governor in combination with intel_pstate/x86 Date: Wed, 18 May 2016 01:18:30 +0200 Message-ID: <573BA6C6.901@intel.com> References: <573B4C2A.4010205@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mga04.intel.com ([192.55.52.120]:53711 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751991AbcEQXSe (ORCPT ); Tue, 17 May 2016 19:18:34 -0400 In-Reply-To: Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: sedat.dilek@gmail.com Cc: "Pandruvada, Srinivas" , linux-pm@vger.kernel.org On 5/18/2016 1:16 AM, Sedat Dilek wrote: > On 5/17/16, Rafael J. Wysocki wrote: >> On 5/17/2016 5:30 PM, Sedat Dilek wrote: >>> Hi, >> Hi, >> >> You have a broken address of linux-pm (it leads to nowhere). >> > Grrr, yeah you are right. > >>> I wonder if the Kconfig logic is correct when using >>> CONFIG_CPU_FREQ_DEFAULT_GOV_SCHEDUTIL=y in combination with >>> intel_pstate driver for X86 architecture >>> >>> The available scaling-governors for intel_pstate are: performance >>> powersave. >>> >>> Only acpi-cpufreq can use the new schedutil governor. >> The right way to say that would be that intel_pstate doesn't work with >> cpufreq governors. >> >> scalling_governor is just used by intel_pstate as an interface for >> choosing the mode it works in and it always uses its own built-in >> "governor". And BTW, intel_pstate "powersave" is not the same as the >> cpufreq's "powersave" even. >> >>> Shouldn't it be prevented from selecting schedutil governor as default >>> when CONFIG_X86_INTEL_PSTATE=y is set? >> That should apply to "ondemand" too and it doesn't, so no. >> >> "schedutil" is just a regular cpufreq governor and it doesn't care about >> intel_pstate. >> >>> It makes no real sense to me. >>> >>> Ubuntu has in it's kernels CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE=y. >>> >>> What are the alternatives? >>> Set CONFIG_CPU_FREQ_DEFAULT_GOV_USERSPACE=y. >> You can choose every cpufreq governor as the default. There are 6 of >> then now in the tree. >> >>> BTW, I cannot change my scaling-driver... >>> ...intel_pstate -> acpi-cpufreq... >>> >>> root# for p in policy0 policy1 policy2 policy3 ; do LC_ALL=C echo -n >>> acpi-cpufreq > /sys/devices/system/cpu/cpufreq/${p}/scaling_driver ; >>> done >>> >>> Attached is also a modified /etc/init.d/ondemand script from my >>> Ubuntu/precise AMD64 to use and fallback to schedutil governor. >> No, you can't change the scaling driver this way. >> >> It actually is not possible to change from intel_pstate to anything else >> now. To run without intel_pstate, you need to add >> "intel_pstate=disable" to the kernel command line. >> > OK, I will try intel_pstate=disable in my k-c-l. > > Is there no way to switch between acpi-cpufreq and intel_pstate on the fly? No, there's no way to do that ATM. > Did not look in the Kconfig sections... > Can I built both as modules? > Then unload and load the other? No, intel_pstate can't be built as a module. Thanks, Rafael