From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263000AbVALCKV (ORCPT ); Tue, 11 Jan 2005 21:10:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263002AbVALCKV (ORCPT ); Tue, 11 Jan 2005 21:10:21 -0500 Received: from mail.joq.us ([67.65.12.105]:2471 "EHLO sulphur.joq.us") by vger.kernel.org with ESMTP id S263000AbVALCKM (ORCPT ); Tue, 11 Jan 2005 21:10:12 -0500 To: Ingo Molnar Cc: Chris Wright , Christoph Hellwig , Andrew Morton , Lee Revell , paul@linuxaudiosystems.com, arjanv@redhat.com, alan@lxorguk.ukuu.org.uk, linux-kernel@vger.kernel.org Subject: Re: [PATCH] [request for inclusion] Realtime LSM References: <200501071620.j07GKrIa018718@localhost.localdomain> <1105132348.20278.88.camel@krustophenia.net> <20050107134941.11cecbfc.akpm@osdl.org> <20050107221059.GA17392@infradead.org> <20050107142920.K2357@build.pdx.osdl.net> <87mzvkxxck.fsf@sulphur.joq.us> <20050111212139.GA22817@elte.hu> From: "Jack O'Quin" Date: Tue, 11 Jan 2005 20:10:26 -0600 In-Reply-To: <20050111212139.GA22817@elte.hu> (Ingo Molnar's message of "Tue, 11 Jan 2005 22:21:39 +0100") Message-ID: <87pt0bxur1.fsf@sulphur.joq.us> User-Agent: Gnus/5.1006 (Gnus v5.10.6) XEmacs/21.4 (Corporate Culture, linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ingo Molnar writes: > * Jack O'Quin wrote: > >> Here are the corrected results... >> >> With -R Without -R Without -R >> (SCHED_FIFO) (nice -20) (nice --20) >> >> XRUN Count . . . . . . . . . : 2 2837 43 >> Delay Maximum . . . . . . . . : 3130 usecs 5038044 usecs 501374 usecs >> Cycle Maximum . . . . . . . . : 960 usecs 18802 usecs 1036 usecs > > what kind of non-audio workload was there during this test? 43 xruns > arent nice but arent that bad either. Nothing heavy, but I was reading mail, and switching GNOME workspaces. Workspace switching often caused trouble in the past, but I had already hacked my X server not to run nice -10 (which is the Debian default). > plus, is it 100% sure that all audio threads inherited the nice --20 > priority - including the client threads? Nornally jackd does a > setscheduler for the client threads so that they get boosted to > SCHED_FIFO, but there is no parallel to that in the nice --20 case, did > you do that manually (or did you start the clients up from the nice --20 > shell too?)) Having totally screwed up the test once already, I hesitate to claim 100% surety about anything. :-) The script starts all the clients. I ran it with nice --20. I just started it again so I could check the nice values with GNOME system monitor. They all have -20, AFAICS. There are a bunch of them at -20, and I don't see any process that looks relevant without -20. > If the nice --20 priority setup is perfect and there are still xruns > then could you try the following hack, change this line in > kernel/sched.c: > > #define STARVATION_LIMIT (MAX_SLEEP_AVG) > > to: > > #define STARVATION_LIMIT 0 > > this will turn off starvation checking, for testing purposes. (to see > whether there's anything else but anti-starvation causing xruns.) No problem (it might be Thursday before I have time to try it). -- joq