From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758670AbZHROAi (ORCPT ); Tue, 18 Aug 2009 10:00:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751697AbZHROAh (ORCPT ); Tue, 18 Aug 2009 10:00:37 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:50892 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751358AbZHROAh (ORCPT ); Tue, 18 Aug 2009 10:00:37 -0400 Date: Tue, 18 Aug 2009 16:00:22 +0200 From: Ingo Molnar To: "Metzger, Markus T" Cc: Peter Zijlstra , "tglx@linutronix.de" , "hpa@zytor.com" , "markus.t.metzger@gmail.com" , "linux-kernel@vger.kernel.org" , Paul Mackerras Subject: Re: [PATCH] perf_counter: Fix a race on perf_counter_ctx Message-ID: <20090818140022.GB13013@elte.hu> References: <20090808120315.GA14086@elte.hu> <928CFBE8E7CB0040959E56B4EA41A77EC1BFF464@irsmsx504.ger.corp.intel.com> <20090810134608.GA8295@elte.hu> <928CFBE8E7CB0040959E56B4EA41A77EC1BFF78D@irsmsx504.ger.corp.intel.com> <928CFBE8E7CB0040959E56B4EA41A77EC1CB7725@irsmsx504.ger.corp.intel.com> <1250600348.7583.280.camel@twins> <1250600385.7583.281.camel@twins> <928CFBE8E7CB0040959E56B4EA41A77EC1CB7775@irsmsx504.ger.corp.intel.com> <1250602664.7583.293.camel@twins> <928CFBE8E7CB0040959E56B4EA41A77EC1CB77C8@irsmsx504.ger.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <928CFBE8E7CB0040959E56B4EA41A77EC1CB77C8@irsmsx504.ger.corp.intel.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Metzger, Markus T wrote: > Well, that would push out the limit a bit, but it would still be > quite fragile. > > Currently, I'm not sure that this (i.e. that the interrupt > handling takes too long) is the underlying problem of the hangs > that I'm seeing. I havent seen a plausible theory yet about why an actual lockup would happen on your box. Does the timer IRQ perhaps slow down to such a degree that it can never make progress and gets re-triggered again and again? We saw such things with the function tracer. Did the sampling of kernel-mode tasks ever work with the old BTS code? Ingo