From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266848AbUGLO1z (ORCPT ); Mon, 12 Jul 2004 10:27:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266851AbUGLO1y (ORCPT ); Mon, 12 Jul 2004 10:27:54 -0400 Received: from mail003.syd.optusnet.com.au ([211.29.132.144]:19341 "EHLO mail003.syd.optusnet.com.au") by vger.kernel.org with ESMTP id S266848AbUGLO1p (ORCPT ); Mon, 12 Jul 2004 10:27:45 -0400 Message-ID: <40F29FCF.3070302@kolivas.org> Date: Tue, 13 Jul 2004 00:27:27 +1000 From: Con Kolivas User-Agent: Mozilla Thunderbird 0.7.1 (X11/20040626) X-Accept-Language: en-us, en MIME-Version: 1.0 To: "Martin J. Bligh" Cc: linux-kernel@vger.kernel.org, akpm@osdl.org Subject: Re: [PATCH] Instrumenting high latency References: <75270000.1089642258@[10.10.2.4]> In-Reply-To: <75270000.1089642258@[10.10.2.4]> 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="------------enig69C2144141E9E79376296BB7" 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) --------------enig69C2144141E9E79376296BB7 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Martin J. Bligh wrote: >>Because of the recent discussion about latency in the kernel I asked >>William Lee Irwin III to help create some instrumentation to determine >>where in the kernel there were still sustained periods of non-preemptible >>code. He hacked together this simple patch which times periods according >>to the preempt count. Hopefully we can use this patch in the advice of >>Linus to avoid the "mental masturbation" at guessing where latency is >>and track down real problem areas. > > > Is this much different from Rick's schedstat's work, which was itself based > on some earlier patches by Bill? I'd hate to end up with two sets of patches, > and schedstats seemed pretty comprehensive to me. He's on vacation, but his > stuff is here, if you want to take a look: > > http://eaglet.rain.com/rick/linux/schedstats/ No I remember his work and this is tackling it via a different area if I recall correctly. He was looking at scheduler latencies as opposed to non-preemptible kernel code. Con --------------enig69C2144141E9E79376296BB7 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 iD8DBQFA8p/SZUg7+tp6mRURAjg1AJ4qnmDXtG0oDTFs0DGmGueRVb78dACeKIgM vq9mQEouK5EJL8ltAfeIzYU= =4XDn -----END PGP SIGNATURE----- --------------enig69C2144141E9E79376296BB7--