From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762127AbYCABAK (ORCPT ); Fri, 29 Feb 2008 20:00:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752973AbYCAA75 (ORCPT ); Fri, 29 Feb 2008 19:59:57 -0500 Received: from gv-out-0910.google.com ([216.239.58.186]:57040 "EHLO gv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752715AbYCAA74 (ORCPT ); Fri, 29 Feb 2008 19:59:56 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=f76c0/A6c35r/85fKAMowod7QGFxgEd2m/M7hX3pWp2lgN8zG4ZOrMe0IcxpY0Bi8RK/I61if/628ffDbJTS6BENn9xjTKlAJrZqLs4UE/kIZR2IE6+FDkl81/8lJzzhzEPfXL93S8z7R8CousaulFBMbwbc6feGCH99TlZrI8A= Message-ID: Date: Sat, 1 Mar 2008 03:59:53 +0300 From: "Alexey Zaytsev" To: "Ingo Molnar" Subject: Re: printk timestamps jumping back and forth in 2.6.25-rc. Cc: "Thomas Gleixner" , lkml , "Arjan van de Ven" In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20080228201315.GA30736@elte.hu> <20080228201613.GA30999@elte.hu> <20080229194547.GC21249@elte.hu> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Mar 1, 2008 at 3:42 AM, Alexey Zaytsev wrote: > > On Fri, Feb 29, 2008 at 10:45 PM, Ingo Molnar wrote: > > > > * Alexey Zaytsev wrote: > > > > > > > > > On Thu, Feb 28, 2008 at 11:16 PM, Ingo Molnar wrote: > > > > > > > > * Ingo Molnar wrote: > > > > > > > > > > Anything else I can do? > > > > > > > > > > yes, please test the patch below - does it fix the problem? > > > > > > The patch worked well, thanks > > > > > > I still observe some uneven mouse behaviour during compilations (linux > > > kernel, make -j 6), like, when I slowly move the mouse, it would stop > > > for a split of a second every few seconds (the intervals are not > > > equal). On 2.6.23/24 it works very smooth. Of course, I can't say that > > > the scheduler is to be blamed. It was only my assumption because I > > > thought I might be confused by the non-monotinic time, which I see is > > > not the case. Any ideas, how to debug this? > > > > could you try latencytop, what does it say, what type of scheduler (and > > other) delays are there? > > > > I'm not sure I fully understand how to use this tool. > There are clearly two possible options to the utility, > --unknown and -d, but I still have no idea what they do.. > > Does the latencytop-0.3 actually work? I my case the upper half of the > window is always empty. The lower half shows always one line, like > > Scheduler: waiting for cpu \t \t \t \t $some_val $some_val > > The two values are always identical. > > In the 2.6.24 case, the values for Xorg are always around 20 ms > when a make -j 6 is runig in parallel. For the 2.6.25 the > values jump from 100 ms to over 1000 ms. > > Later I mounted a tmpfs and run the compilation (from root) there > (swap turned off). This time the Xorg latency was usually less then > 30 ms, but the gnome-terminal (running from an other user) was not > that lucky with latencies around 500-1000 ms. Now I ran the same compilation > from user, and the latencies came back to what I observed before, with > gnome-terminal being about 30-50 and Xorg jumping from 100 to now > over 2000. The latencytop and some daemons runnig as different users > also had comparable latencyes. > > Yes, fair group scheduler enabled, the config can be seen here: > http://romomatic.osuosl.org/share/xl0/config-2.6.25-rc3 > > I"ll now recompile with fair group scheduler disabled, just to be sure. > Yes, with the group scheduler disabled, the latencies for both Xorg and gnome-terminal do net exceed 15 ms. And the mouse is also smooth.