From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754626AbYDWJrQ (ORCPT ); Wed, 23 Apr 2008 05:47:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751261AbYDWJrE (ORCPT ); Wed, 23 Apr 2008 05:47:04 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:44378 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751063AbYDWJrC (ORCPT ); Wed, 23 Apr 2008 05:47:02 -0400 Date: Wed, 23 Apr 2008 11:46:44 +0200 From: Ingo Molnar To: Frans Pop Cc: Peter Zijlstra , linux-kernel@vger.kernel.org, Mike Galbraith , Richard Jonsson Subject: Re: [git pull] scheduler changes for v2.6.26 Message-ID: <20080423094644.GB23293@elte.hu> References: <20080419181304.GB21353@elte.hu> <200804211831.29976.elendil@planet.nl> <20080421194359.GD8770@elte.hu> <200804231136.50639.elendil@planet.nl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200804231136.50639.elendil@planet.nl> User-Agent: Mutt/1.5.17 (2007-11-01) 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 * Frans Pop wrote: > If I enable tracing with these settings, I get data in both trace > *and* in latency_trace. Is the last correct? From > http://lkml.org/lkml/2008/2/10/43 I got the impression that file > should only be used if the "wakeup" tracer is active. yeah, that's the intended behavior. 'trace' and 'latency_trace' are two kinds of 'views' on the same set of tracer data (with a different output format). They are both non-destructive - i.e. they dont deplete the trace buffers. there's even a third view: 'trace_pipe' - which depletes the trace buffers and can be used to pipe trace data into a larger file: cat trace_pipe > /tmp/large-trace.txt i guess it would be less confusing if 'trace' and 'latency_trace' was just a single 'view' and its behavior depended on iter_ctl settings. (In fact, we could probably just get rid of latency_trace - it is a leftover from -rt.) > From the last run I've got three traces with 50000 entries (about a > minute worth each). Traces 1 and 2 should each have two skips and > trace 3 should have four. I've saved both the trace and latency_trace > (ltrace) files. > > They are available at: > http://people.debian.org/~fjp/tmp/kernel/sched/. thanks, we'll have a look. > BTW, did either of you actually look at the traces I sent for .24? I > never got any feedback on those. hm, i looked at them - i thought i mailed you about that but indeed i didnt (sorry about that) - the traces were too short in scope - they just covered a few dozen milliseconds in scope, while your description said that the problem occured seconds into the trace. > P.S. I've got group scheduling active in this config as my tests with > .24 showed that did not make any difference. Can rerun without if > needed. no need to rerun - but if you do the next test it might make sense to disable it, just to reduce the number of variables. another thing - Peter observed skipping on NOHZ. Does your skipping go away if you boot with 'nohz' and/or with CONFIG_NOHZ=y disabled in the .config? Ingo