From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030831AbXCNJne (ORCPT ); Wed, 14 Mar 2007 05:43:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030832AbXCNJne (ORCPT ); Wed, 14 Mar 2007 05:43:34 -0400 Received: from hermes2.dur.ac.uk ([129.234.8.21]:49162 "EHLO hermes2.dur.ac.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030831AbXCNJnd (ORCPT ); Wed, 14 Mar 2007 05:43:33 -0400 Date: Wed, 14 Mar 2007 09:47:11 +0000 From: Ash Milsted To: "Chris Friesen" Cc: Lee Revell , Con Kolivas , linux kernel mailing list , ck list Subject: Re: [ck] RSDL v0.30 cpu scheduler for mainline kernels Message-Id: <20070314094711.d0d3a580.thatistosayiseenem@gawab.com> In-Reply-To: <45F6E34E.9020308@nortel.com> References: <200703121058.11966.kernel@kolivas.org> <20070313153514.428dc3e1.thatistosayiseenem@gawab.com> <75b66ecd0703130853p4c7d029en2405caee4447d29e@mail.gmail.com> <45F6E34E.9020308@nortel.com> X-Mailer: Sylpheed 2.3.1 (GTK+ 2.10.9; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-DurhamAcUk-MailScanner: Found to be clean, Found to be clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 13 Mar 2007 11:45:50 -0600 "Chris Friesen" wrote: > Lee Revell wrote: > > > Sounds like Wengophone is broken. It should be using RT threads for > > time critical work, as JACK and Ardour2 are doing. > > If the app has root privileges to set RT policy, then it could also set > deeply negative nice values as well. > > Doesn't reallly help the regular user with no privileges. > > Chris Well my distro (Arch) does have the relevant PAM support for giving users realtime capabilities, but naturally Wengophone is not designed to make use of them (does any internet phone do this?). The main problem is that it worked fine on mainline and does not with RSDL, and even boosting it to nice -19 (with root privs) makes no difference (although I only tested nice -19 with the slightly dodgy patch Con posted for Mike Galbraith, that patch reportedly only affects a few positive nice values). Two possibilities occur to me: 1. RSDL just isn't giving sched_other tasks as low latency as mainline (Wengophone is not using much CPU time from as far as top can tell). 2. The problem is actually caused by increased network latency somehow caused by RSDL (this is an internet phone). I would like to add that the problem seems to be latency *spikes* that occur when there is sudden activity in another app (say, I open a folder in nautilus) that was previously largely idle. I suppose if Con does what he says and reduces latency overall, this problem might disappear. For now, of course, I hope his neck gets better :)