From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754667Ab0CWPS6 (ORCPT ); Tue, 23 Mar 2010 11:18:58 -0400 Received: from casper.infradead.org ([85.118.1.10]:48455 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754432Ab0CWPS5 convert rfc822-to-8bit (ORCPT ); Tue, 23 Mar 2010 11:18:57 -0400 Subject: Re: [PATCH] perf_events: fix bug in AMD per-cpu initialization From: Peter Zijlstra To: Stephane Eranian Cc: linux-kernel@vger.kernel.org, mingo , paulus@samba.org, davem@davemloft.net, fweisbec@gmail.com, robert.richter@amd.com, perfmon2-devel@lists.sf.net, eranian@gmail.com, "hpa@zytor.com" , Thomas Gleixner , Manfred Spraul In-Reply-To: References: <4ba0a646.25e2660a.1b25.531c@mx.google.com> <1268869631.9440.282.camel@laptop> <1269353485.5109.48.camel@twins> <1269356868.5109.66.camel@twins> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Tue, 23 Mar 2010 16:18:26 +0100 Message-ID: <1269357506.5109.84.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2010-03-23 at 16:12 +0100, Stephane Eranian wrote: > On Tue, Mar 23, 2010 at 4:07 PM, Peter Zijlstra wrote: > > On Tue, 2010-03-23 at 15:55 +0100, Stephane Eranian wrote: > >> What's the point of CPU_ONLINE vs. CPU_STARTING if you're saying the > >> former is never right? Why not move CPU_ONLINE to the right place and > >> drop CPU_STARTING? > > > > Its right for a lot of things, just not for perf, we need to be ready > > and done by the time the cpu starts scheduling. > > > You mean they need to wait until after the cpu starts scheduling? > As opposed to being called just before it starts scheduling. As in it doesn't really matter for them, and the CPU_ONLINE call is convenient in that it allows the callback to schedule too.