From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759911Ab1JGLWU (ORCPT ); Fri, 7 Oct 2011 07:22:20 -0400 Received: from merlin.infradead.org ([205.233.59.134]:46509 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759808Ab1JGLWT convert rfc822-to-8bit (ORCPT ); Fri, 7 Oct 2011 07:22:19 -0400 Subject: Re: [PATCH 07/12] perf_events: add LBR software filter support for Intel X86 From: Peter Zijlstra To: Stephane Eranian Cc: Andi Kleen , linux-kernel@vger.kernel.org, mingo@elte.hu, acme@redhat.com, ming.m.lin@intel.com, robert.richter@amd.com, ravitillo@lbl.gov, "masami.hiramatsu.pt" Date: Fri, 07 Oct 2011 13:21:59 +0200 References: <1317912555-9559-1-git-send-email-eranian@google.com> <1317912555-9559-8-git-send-email-eranian@google.com> <20111006153229.GJ14482@one.firstfloor.org> <1317984122.31132.6.camel@twins> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT X-Mailer: Evolution 3.0.3- Message-ID: <1317986519.31132.13.camel@twins> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2011-10-07 at 13:18 +0200, Peter Zijlstra wrote: > > Yeah, depending on the depth of the LBR. But then what happens, you > > decode an instruction that is not what was executed. > > Right, and Andi's concern is that this might cause our instruction > decoder to blow up, or worse. That is, we have a fair confidence that its capable of correctly decoding correct streams, but I understood from Masami that they haven't actually tried feeding it crap.