Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753408AbYLLTq0 (ORCPT ); Fri, 12 Dec 2008 14:46:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751464AbYLLTqQ (ORCPT ); Fri, 12 Dec 2008 14:46:16 -0500 Received: from zrtps0kn.nortel.com ([47.140.192.55]:51309 "EHLO zrtps0kn.nortel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751267AbYLLTqP (ORCPT ); Fri, 12 Dec 2008 14:46:15 -0500 Message-ID: <4942BF69.4030402@nortel.com> Date: Fri, 12 Dec 2008 13:45:45 -0600 From: "Chris Friesen" User-Agent: Mozilla Thunderbird 1.0.2-6 (X11/20050513) X-Accept-Language: en-us, en MIME-Version: 1.0 To: eranian@gmail.com CC: Peter Zijlstra , Vince Weaver , Ingo Molnar , linux-kernel@vger.kernel.org, Thomas Gleixner , Andrew Morton , Eric Dumazet , Robert Richter , Arjan van de Veen , Peter Anvin , Paul Mackerras , "David S. Miller" Subject: Re: [patch] Performance Counters for Linux, v3 References: <20081211155230.GA4230@elte.hu> <1229070345.12883.12.camel@twins> <7c86c4470812120059s7f8e64a6h91ebeadbf938858d@mail.gmail.com> <1229073834.12883.41.camel@twins> <7c86c4470812120942x607a74f7w9f823adecbd73b85@mail.gmail.com> <7c86c4470812121001i765d663bq6db3080b633a1eef@mail.gmail.com> In-Reply-To: <7c86c4470812121001i765d663bq6db3080b633a1eef@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 12 Dec 2008 19:45:50.0016 (UTC) FILETIME=[3C1B1C00:01C95C92] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 745 Lines: 24 stephane eranian wrote: > What happens in the following test case: > > - 2-way system (cpu0, cpu1) > > - on cpu0, two processes P1, P2, each self-monitoring and counting event E1. > Event E1 can only be measured on counter C1. > > - on cpu1, there is a cpu-wide session, monitoring event E1, thus using C1 > > - the scheduler decides to migrate P1 onto CPU1. You now have a > conflict on C1. > > How is this managed? Prevent the load balancer from moving P1 onto cpu1? Chris -- 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/