Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761684AbZATPEv (ORCPT ); Tue, 20 Jan 2009 10:04:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755989AbZATPEm (ORCPT ); Tue, 20 Jan 2009 10:04:42 -0500 Received: from mx3.mail.elte.hu ([157.181.1.138]:58776 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755867AbZATPEl (ORCPT ); Tue, 20 Jan 2009 10:04:41 -0500 Date: Tue, 20 Jan 2009 16:04:08 +0100 From: Ingo Molnar To: Steven Rostedt Cc: Kevin Shanahan , Avi Kivity , "Rafael J. Wysocki" , Linux Kernel Mailing List , Kernel Testers List , Kevin Shanahan , Mike Galbraith , Peter Zijlstra , =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker Subject: Re: [Bug #12465] KVM guests stalling on 2.6.28 (bisected) Message-ID: <20090120150408.GD21931@elte.hu> References: <1232410363.4768.21.camel@kulgan.wumi.org.au> <20090120113546.GA26571@elte.hu> <1232455343.4895.4.camel@kulgan.wumi.org.au> <20090120125652.GA1457@elte.hu> <20090120130714.GA11048@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean 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=3.2.3 -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 Content-Length: 1164 Lines: 31 * Steven Rostedt wrote: > On Tue, 20 Jan 2009, Ingo Molnar wrote: > > Another test would be to build the scheduler latency tracer into your > > kernel: > > > > CONFIG_SCHED_TRACER=y > > > > And enable it via: > > > > echo wakeup > /debug/tracing/current_tracer > > > > and you should be seeing the worst-case scheduling latency traces in > > /debug/tracing/trace, and the largest observed latency will be in > > /debug/tracing/tracing_max_latency [in microseconds]. > > Note, the wakeup latency only tests realtime threads, since other > threads can have other issues for wakeup. I could change the wakeup > tracer as wakeup_rt, and make a new "wakeup" that tests all threads, but > it may be difficult to get something accurate. hm, that's a significant regression then. The latency tracer used to measure the highest-prio task in the system - be that RT or non-rt. Ingo -- 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/