Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762047Ab2FHJfV (ORCPT ); Fri, 8 Jun 2012 05:35:21 -0400 Received: from mail-bk0-f46.google.com ([209.85.214.46]:48506 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759779Ab2FHJfT (ORCPT ); Fri, 8 Jun 2012 05:35:19 -0400 Date: Fri, 8 Jun 2012 11:35:13 +0200 From: Ingo Molnar To: Peter Zijlstra Cc: Stephane Eranian , linux-kernel@vger.kernel.org, andi@firstfloor.org, mingo@elte.hu, ming.m.lin@intel.com Subject: Re: [PATCH] perf/x86: check ucode before disabling PEBS on SandyBridge Message-ID: <20120608093513.GA22520@gmail.com> References: <20120607071531.GA4849@quad> <1339064319.23343.13.camel@twins> <1339065932.23343.18.camel@twins> <1339067757.23343.21.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1339067757.23343.21.camel@twins> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 928 Lines: 28 * 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 ... Thanks, 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/