Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756551AbZFWJrr (ORCPT ); Tue, 23 Jun 2009 05:47:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752574AbZFWJr1 (ORCPT ); Tue, 23 Jun 2009 05:47:27 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:49107 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751765AbZFWJr1 (ORCPT ); Tue, 23 Jun 2009 05:47:27 -0400 Date: Tue, 23 Jun 2009 11:47:17 +0200 From: Ingo Molnar To: Yong Wang Cc: eranian@gmail.com, "Wang, Yong Y" , Peter Zijlstra , LKML , Paul Mackerras , Andi Kleen Subject: Re: perf_counter Atom patch Message-ID: <20090623094717.GA30634@elte.hu> References: <7c86c4470906221326j6edbf9f3g5d65e96d86aaf7ab@mail.gmail.com> <9F0C1DB20AFA954FA1DA05309350433D7B2584D1@pdsmsx503.ccr.corp.intel.com> <7c86c4470906230045k578bc146wa0e09e4094d937a5@mail.gmail.com> <20090623075959.GA23534@ywang-moblin2.bj.intel.com> <7c86c4470906230127g4f574b61p24f109c7a94c6e39@mail.gmail.com> <7c86c4470906230140p35ce043fw24e0c20651568f31@mail.gmail.com> <20090623085321.GC23534@ywang-moblin2.bj.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090623085321.GC23534@ywang-moblin2.bj.intel.com> User-Agent: Mutt/1.5.18 (2008-05-17) 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=3.2.5 -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 Content-Length: 1995 Lines: 54 * Yong Wang wrote: > On Tue, Jun 23, 2009 at 10:40:45AM +0200, stephane eranian wrote: > > Yong, > > > > On Tue, Jun 23, 2009 at 10:27 AM, stephane > > eranian wrote: > > > Hi, > > > > > > On Tue, Jun 23, 2009 at 9:59 AM, Yong Wang wrote: > > >> On Tue, Jun 23, 2009 at 09:45:03AM +0200, stephane eranian wrote: > > >>> > > >>> Unfortunately, I don't have a N270 to compare with your results. > > >>> We need to verify whether or not N270 implements the fixed counters. > > >>> Does it report architected perfmon v3 or v1? > > >>> > > >> > > >> All Atom processors report perfmon v3 as specified in SDM. N270 is no > > >> exception. > > >> > > > V3 does not set a minimal number of fixed counters, could be zero. But > > > that seems > > > odd. Let me ask around. > > > > > Second thought on this: > > x86_pmu.num_counters_fixed = > > max((int)edx.split.num_counters_fixed, 3); > > > > rdmsrl(MSR_CORE_PERF_GLOBAL_CTRL, x86_pmu.intel_ctrl); > > > > > > Forcing num_counter_fixed is not enough, you need to make sure > > they are actually activated in GLOBAL_CTRL, i.e., make sure bits > > 32-34 are set in intel_ctrl. Depending on which machine you're > > on, the power on value for GLOBAL_CTRL changes. The correct > > value for it should be that ONLY generic counters are on by > > default. > > > > Oh, this might be why fixed counter do not work on my Atom box. I > will look into it. [...] Thanks - having a different bootup default for the global ctrl indeed sounds like a good and plausible explanation - please send a patch for that if you've tested it, removing that quirk and adding the global-enable ctrl logic. Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/