From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752590AbXC3JYl (ORCPT ); Fri, 30 Mar 2007 05:24:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752381AbXC3JYk (ORCPT ); Fri, 30 Mar 2007 05:24:40 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:38023 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752590AbXC3JYk (ORCPT ); Fri, 30 Mar 2007 05:24:40 -0400 Date: Fri, 30 Mar 2007 11:24:34 +0200 From: Ingo Molnar To: Roland Dreier Cc: linux-kernel@vger.kernel.org Subject: Re: Early hang with 2.6.21-rc4-rt1 Message-ID: <20070330092434.GA20903@elte.hu> References: <20070325073146.GB10734@elte.hu> <20070327192400.GB31695@elte.hu> <20070330090206.GA14324@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070330090206.GA14324@elte.hu> User-Agent: Mutt/1.4.2.2i X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.0.3 -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Ingo Molnar wrote: > > Great, thanks ... I'm not sure which of the 2 patches fixed things, > > but I now got the following trace. I've not really analyzed this, > > but it definitely looks like tun_init() is doing something fishy... > > ("149776 us maximum-latency"!!) > > best would be to enable FUNCTION_TRACING and to do: > > echo 1 > /proc/sys/kernel/trace_enabled > echo 1 > /proc/sys/kernel/mcount_enabled > > this will give you an exact trace of what happened, in > /proc/latency_trace. btw., if you use -rt, it makes sense to disable the UNWIND options in the .config - the unwinder causes quite some overhead at places. Ingo