From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266013AbUGJBAs (ORCPT ); Fri, 9 Jul 2004 21:00:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266018AbUGJBAs (ORCPT ); Fri, 9 Jul 2004 21:00:48 -0400 Received: from mail015.syd.optusnet.com.au ([211.29.132.161]:13244 "EHLO mail015.syd.optusnet.com.au") by vger.kernel.org with ESMTP id S266013AbUGJBAq (ORCPT ); Fri, 9 Jul 2004 21:00:46 -0400 Message-ID: <40EF3FAA.5000907@kolivas.org> Date: Sat, 10 Jul 2004 11:00:26 +1000 From: Con Kolivas User-Agent: Mozilla Thunderbird 0.7.1 (X11/20040626) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Arjan van de Ven Subject: Re: [announce] [patch] Voluntary Kernel Preemption Patch References: <20040709182638.GA11310@elte.hu> In-Reply-To: <20040709182638.GA11310@elte.hu> X-Enigmail-Version: 0.84.1.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig253EC76B800EAF7B7A2A034E" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig253EC76B800EAF7B7A2A034E Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Ingo Molnar wrote: > as most of you are probably aware of it, there have been complaints on > lkml that the 2.6 kernel is not suitable for serious audio work due to > high scheduling latencies (e.g. the Jackit people complained). I took a > look at latencies and indeed 2.6.7 is pretty bad - latencies up to 50 > msec (!) can be easily triggered using common workloads, on fast 2GHz+ > x86 system - even when using the fully preemptible kernel! > > to solve this problem, Arjan van de Ven and I went over various kernel > functions to determine their preemptability and we re-created from > scratch a patch that is equivalent in performance to the 2.4 lowlatency > patches but is different in design, impact and approach: > > http://redhat.com/~mingo/voluntary-preempt/voluntary-preempt-2.6.7-bk20-H2 Looks nice. I think you may have mixed up your trees. I think this change is the cfq bad allocation fix which I dont think is part of your voluntary preemption patch: --- linux/drivers/block/cfq-iosched.c.orig +++ linux/drivers/block/cfq-iosched.c Otherwise, cheers! I'll give it a bit of a run and see what numbers come up. Con --------------enig253EC76B800EAF7B7A2A034E Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFA7z+qZUg7+tp6mRURAkDOAJ9UOb3tSIRUwQFY8n83gkv/TYQbjwCeIkYv uNcLaxXWdcbV7ieYc7m5duk= =ZKOb -----END PGP SIGNATURE----- --------------enig253EC76B800EAF7B7A2A034E--