Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752194AbaBEUAp (ORCPT ); Wed, 5 Feb 2014 15:00:45 -0500 Received: from smtpauth02.mfg.siteprotect.com ([64.26.60.136]:44733 "EHLO smtpauth02.mfg.siteprotect.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752182AbaBEUAm (ORCPT ); Wed, 5 Feb 2014 15:00:42 -0500 Date: Wed, 5 Feb 2014 15:04:03 -0500 (EST) From: Vince Weaver X-X-Sender: vince@pianoman.cluster.toy To: Peter Zijlstra cc: junk@eslaf.co.uk, alan@lxorguk.ukuu.org.uk, Ingo Molnar , Stephane Eranian , linux-kernel@vger.kernel.org Subject: Re: [PATCH] perf,x86,p6: Add userspace RDPMC quirk for P6 In-Reply-To: <20140205195506.GN2936@laptop.programming.kicks-ass.net> Message-ID: References: <20140205102718.GF3229@twins.programming.kicks-ass.net> <20140205192012.GL2936@laptop.programming.kicks-ass.net> <20140205195506.GN2936@laptop.programming.kicks-ass.net> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-CTCH-Spam: Unknown X-CTCH-RefID: str=0001.0A020202.52F2986A.009A,ss=1,re=0.000,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 5 Feb 2014, Peter Zijlstra wrote: > On Wed, Feb 05, 2014 at 02:37:29PM -0500, Vince Weaver wrote: > > On Wed, 5 Feb 2014, Vince Weaver wrote: > > > > > Has someone actually hit this bug? People used PAPI/perfctr on these > > > machines for years, and it uses rdpmc by default so I would think it would > > > show up if it were an issue. I should check the perfctr code to see if it > > > had some sort of check. > > > > I can verify the perfctr code does have a case for PPRO errata 26, but it > > only disables things on pentium pros with stepping less than 9. > > The doc said 0xB1, right? Should we keep it at that? Its not like > there's a lot of PPro machines left out there, so better safe than > sorry. mfg steping "sB1" which means processor stepping 9. See page 15 of the document linked in the original patch. I used to have a Pentium Pro that was apparently affected by this erratum but not any more. The oldest machine I test perf stuff on is a Pentium II. Vince -- 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/