Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934205Ab2FHKD5 (ORCPT ); Fri, 8 Jun 2012 06:03:57 -0400 Received: from mail-ee0-f46.google.com ([74.125.83.46]:54310 "EHLO mail-ee0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754503Ab2FHKDz convert rfc822-to-8bit (ORCPT ); Fri, 8 Jun 2012 06:03:55 -0400 MIME-Version: 1.0 In-Reply-To: <1339149613.23343.52.camel@twins> References: <20120607071531.GA4849@quad> <1339064319.23343.13.camel@twins> <1339065932.23343.18.camel@twins> <1339067757.23343.21.camel@twins> <20120608093513.GA22520@gmail.com> <1339149613.23343.52.camel@twins> Date: Fri, 8 Jun 2012 12:03:49 +0200 Message-ID: Subject: Re: [PATCH] perf/x86: check ucode before disabling PEBS on SandyBridge From: Stephane Eranian To: Peter Zijlstra Cc: Ingo Molnar , linux-kernel@vger.kernel.org, andi@firstfloor.org, mingo@elte.hu, ming.m.lin@intel.com Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1339 Lines: 31 On Fri, Jun 8, 2012 at 12:00 PM, Peter Zijlstra wrote: > On Fri, 2012-06-08 at 11:35 +0200, Ingo Molnar wrote: >> * Peter Zijlstra wrote: >> >> > On Thu, 2012-06-07 at 12:48 +0200, Stephane Eranian wrote: >> > > >> The warning could also be done on boot. But the check has to be done >> > > >>  when the event is created. >> > > > >> > > > Is this because of the ucode loader not having done its thing yet etc..? >> > >> > Ah, its because you can update ucode at runtime of course. >> > >> > A quick look at the ucode loader doesn't show it having a >> > notifier either, so then yeah we need to check on every event >> > creation :/ >> > >> > Or we could put a hook in the ucode loader. >> >> I'd really suggest the latter - I doubt this will be our only >> ucode dependent quirk, going forward ... > > Yeah, am in the middle of writing that.. I am fine with that. As I found out yesterday, the reality is that the ucode version for SNB vs. SNB-EP differ, so with this mechanism we could customize the callback per CPU model number more easily. -- 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/