From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alex Shi Subject: Re: bltk-game regressions on snb laptop Date: Thu, 18 Apr 2013 14:16:41 +0800 Message-ID: <516F8FC9.8010005@intel.com> References: <516CFA57.3060709@intel.com> <516F42EE.6080802@intel.com> <516F81BD.3030306@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mga01.intel.com ([192.55.52.88]:44461 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754508Ab3DRGRV (ORCPT ); Thu, 18 Apr 2013 02:17:21 -0400 In-Reply-To: Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: Viresh Kumar Cc: Linux PM list , "Brown, Len" , "Wysocki, Rafael J" , Arjan van de Ven , LKP ML On 04/18/2013 01:37 PM, Viresh Kumar wrote: >>> >> About your system: Can you give output of cpufreq-info for v3.8 and >>> >> v3.9-latestrc? >>> >> Your cpus share a clock line or not? >> > >> > Yes our cpu shares a clock line. So the cpufreq-info is same. SNB CPU >> > p-state is per cpu package, and hardware will coordinate the software >> > asking, then decide which cpufreq should be. > Can you paste cpufreq-info output, that will give us a better picture of your > system. will give you turbostat info later. > >> > That's sth I am also confused. Yes, that cpu share a clock line. But >> > Arjan and Len both said affected_cpus should only include the cpu self, >> > because cpu will do hardware coordination for them. > Why? we need a reason for that.... Do they mean Linux shouldn't be aware > of any requirement of freq sync? But why? Nope. acpi_processor_preregister_performance() will read ACPI table and get the p-state coordinate type. I think that is the agreement between kernel and hardware. Maybe the ondemand governor doesn't fit well with the laptop's p-state internal logical. So, there is intel p-state driver for SNB, and it use different internal governor. acpi_processor_preregister_performance(): 715 if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL) 716 pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ALL; 717 else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL) 718 pr->performance->shared_type = CPUFREQ_SHARED_TYPE_HW; 719 else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY) 720 pr->performance->shared_type = CPUFREQ_SHARED_TYPE_ANY; 721 -- Thanks Alex