Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754983AbZFVL5b (ORCPT ); Mon, 22 Jun 2009 07:57:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751729AbZFVL5W (ORCPT ); Mon, 22 Jun 2009 07:57:22 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:42464 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750866AbZFVL5W (ORCPT ); Mon, 22 Jun 2009 07:57:22 -0400 Date: Mon, 22 Jun 2009 13:57:03 +0200 From: Ingo Molnar To: eranian@gmail.com Cc: LKML , Andrew Morton , Thomas Gleixner , Robert Richter , Peter Zijlstra , Paul Mackerras , Andi Kleen , Maynard Johnson , Carl Love , Corey J Ashford , Philip Mucci , Dan Terpstra , perfmon2-devel Subject: Re: II.1 - Fixed counters on Intel Message-ID: <20090622115703.GM24366@elte.hu> References: <7c86c4470906161042p7fefdb59y10f8ef4275793f0e@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7c86c4470906161042p7fefdb59y10f8ef4275793f0e@mail.gmail.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: 1241 Lines: 28 > II/ X86 comments > > 1/ Fixed counters on Intel > > You cannot simply fall back to generic counters if you cannot find > a fixed counter. There are model-specific bugs, for instance > UNHALTED_REFERENCE_CYCLES (0x013c), does not measure the same > thing on Nehalem when it is used in fixed counter 2 or a generic > counter. The same is true on Core. This could be handled via a model specific quirk, if the erratum is serious enough. > You cannot simply look at the event field code to determine > whether this is an event supported by a fixed counters. You must > look at the other fields such as edge, invert, cnt-mask. If those > are present then you have to fall back to using a generic counter > as fixed counters only support priv level filtering. As indicated > above, though, programming UNHALTED_REFERENCE_CYCLES on a generic > counter does not count the same thing, therefore you need to fail > if filters other than priv levels are present on this event. Agreed, we'll fix this. -- 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/