From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756922Ab0GAPvm (ORCPT ); Thu, 1 Jul 2010 11:51:42 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:48732 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756703Ab0GAPvl convert rfc822-to-8bit (ORCPT ); Thu, 1 Jul 2010 11:51:41 -0400 Subject: Re: [RFC PATCH 3/6] perf: Generalize some arch callchain code From: Peter Zijlstra To: Frederic Weisbecker Cc: LKML , Ingo Molnar , Arnaldo Carvalho de Melo , Paul Mackerras , Stephane Eranian , David Miller , Paul Mundt , Will Deacon , Borislav Petkov In-Reply-To: <20100701154922.GC10616@nowhere> References: <1277998562-21366-1-git-send-regression-fweisbec@gmail.com> <1277998562-21366-4-git-send-regression-fweisbec@gmail.com> <1277999161.1917.216.camel@laptop> <20100701154922.GC10616@nowhere> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Thu, 01 Jul 2010 17:51:22 +0200 Message-ID: <1277999482.1917.219.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2010-07-01 at 17:49 +0200, Frederic Weisbecker wrote: > On Thu, Jul 01, 2010 at 05:46:01PM +0200, Peter Zijlstra wrote: > > On Thu, 2010-07-01 at 17:35 +0200, Frederic Weisbecker wrote: > > > - Most archs use one callchain buffer per cpu, except x86 that needs > > > to deal with NMIs. Provide a default perf_callchain_buffer() > > > implementation that x86 overrides. > > > > sparc and power also have NMI like contexts. > > > Ah and the comments suggest it's because pmu interrupts can't nest or so. > Anyway, that's notwithstanding the race that 5th patch fixes. Right, but they could interrupt a software event or the like. But yeah, the whole callchain thing can nest issue is real, thanks for fixing that.