From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756583AbZEKKDT (ORCPT ); Mon, 11 May 2009 06:03:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755632AbZEKKDG (ORCPT ); Mon, 11 May 2009 06:03:06 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:42083 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755401AbZEKKDD (ORCPT ); Mon, 11 May 2009 06:03:03 -0400 Date: Mon, 11 May 2009 12:02:26 +0200 From: Ingo Molnar To: Jaswinder Singh Rajput Cc: mingo@redhat.com, hpa@zytor.com, paulus@samba.org, linux-kernel@vger.kernel.org, robert.richter@amd.com, a.p.zijlstra@chello.nl, tglx@linutronix.de, linux-tip-commits@vger.kernel.org Subject: Re: [tip:perfcounters/core] perf_counter, x86: remove X86_FEATURE_ARCH_PERFMON flag for AMD cpus Message-ID: <20090511100226.GA31041@elte.hu> References: <1241002046-8832-2-git-send-email-robert.richter@amd.com> <1241931753.4796.15.camel@localhost.localdomain> <1241934795.4796.55.camel@localhost.localdomain> <20090510063047.GD30778@elte.hu> <1241938310.4796.67.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1241938310.4796.67.camel@localhost.localdomain> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Jaswinder Singh Rajput wrote: > On Sun, 2009-05-10 at 08:30 +0200, Ingo Molnar wrote: > > * Jaswinder Singh Rajput wrote: > > > > > > #define X86_FEATURE_ARCH_PERFMON (3*32+11) /* Intel Architectural PerfMon */ > > > > should be replaced by > > > > #define X86_FEATURE_ARCH_PERFMON (3*32+11) /* Performace Monitor */ > > > > > > > > All x86 cpus which support performance monitor should set this feature. > > > > > > > > > > Currently X86_FEATURE_ARCH_PERFMON is enabled for >= Intel Core2 > > > > > > But Performance monitor is almost supported by all Intel > > > processors. I am adding few MSRs list for reference to see > > > complete list please check arch/x86/kernel/cpu/cpu_debug.c > > > > I think you are confusing two things: > > > > - The 'architectural perfmon' CPU flag, enumerated in CPUID. (this > > is a relatively new CPUID flag that only Intel CPUs at around > > Core2 and later will report.) > > > > - The concept of 'performance monitoring' - which has been present > > in various x86 CPUs starting at the original Pentium (P5) 15 years > > ago or so. > > > > The X86_FEATURE_ARCH_PERFMON flag is for the architectural perfmon > > CPUID feature. If you execute CPUID you'll get that from the CPU - > > on Core2 and later Intel CPUs. You wont get it on AMD CPUs. You wont > > get it on earlier Intel CPUs. > > > > And since 'Architectural Performance Monitoring' is an Intel only > > thing, it would not be correct to do as if AMD had the same thing. > > AMD has something _similar_, but not quite the same. > > > > Thanks for clarification. > > There is one more way to check performance monitor support for > Intel by using IA32_MISC_ENABLE MSR (0x1A0) bit 7 tells whether > performance monitoring is available or not. > > But IA32_MISC_ENABLE MSR (0x1A0) is not available for Pentium and > P6. > > So better I will add new cpufeature for performance monitoring for > x86: > > X86_FEATURE_PERFMON : Performance monitor support What is the exact wording of IA32_MISC_ENABLE bit 7 in the Intel documents? Ingo