Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267776AbUJLUqD (ORCPT ); Tue, 12 Oct 2004 16:46:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267767AbUJLUox (ORCPT ); Tue, 12 Oct 2004 16:44:53 -0400 Received: from mail.gmx.net ([213.165.64.20]:41421 "HELO mail.gmx.net") by vger.kernel.org with SMTP id S267776AbUJLUoi (ORCPT ); Tue, 12 Oct 2004 16:44:38 -0400 X-Authenticated: #4512188 Message-ID: <416C422F.6030101@gmx.de> Date: Tue, 12 Oct 2004 22:44:31 +0200 From: "Prakash K. Cheemplavam" User-Agent: Mozilla Thunderbird 0.8 (X11/20040929) X-Accept-Language: de-DE, de, en-us, en MIME-Version: 1.0 To: Nick Piggin CC: Jens Axboe , "Ronny V. Vindenes" , ck@vds.kolivas.org, linux-kernel@vger.kernel.org, Andrew Morton Subject: Re: CFQ v2 high cpu load fix(?) References: <1097579760.4086.27.camel@tentacle125.gozu.lan> <416BBF48.4070102@yahoo.com.au> <20041012121227.GA1754@suse.de> <416BCE4A.7060403@yahoo.com.au> In-Reply-To: <416BCE4A.7060403@yahoo.com.au> X-Enigmail-Version: 0.86.0.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig77F5054025E92F7A4470AC2A" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2355 Lines: 71 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig77F5054025E92F7A4470AC2A Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Nick Piggin schrieb: > Jens Axboe wrote: > >> On Tue, Oct 12 2004, Nick Piggin wrote: >> >>> Ronny V. Vindenes wrote: >>> >>>> >>>> --- patches/linux-2.6.9-rc4-ck1/drivers/block/ll_rw_blk.c >>>> 2004-10-12 12:25:09.798003278 +0200 >>>> +++ linux-2.6.9-rc4-ck1/drivers/block/ll_rw_blk.c 2004-10-12 >>>> 12:25:42.959479479 +0200 >>>> @@ -100,7 +100,7 @@ >>>> nr = q->nr_requests; >>>> q->nr_congestion_on = nr; >>>> >>>> - nr = q->nr_requests - (q->nr_requests / 8) - 1; >>>> + nr = q->nr_requests - (q->nr_requests / 8) - >>>> (q->nr_requests/16)- 1; >>>> if (nr < 1) >>>> nr = 1; >>>> q->nr_congestion_off = nr; >>> >>> >>> >>> I thought this first hunk looked like a good idea when Arjan sent the >>> patch. Can you check if it alone helps your problem? >> >> >> >> Yeah agree, it's a good idea to leave a bit of air between congestion on >> and off. Fully explains the cfq v2 excessive sys time for some >> workloads, which is extra nice. >> > > Cool. Can you queue up a patch for when -mm opens again, or shall I? > I can't imagine it should cause any problems but a bit of testing > would be wise. Just as a feedback: I applied the first hunk of that patch to 2.6.9-rc4-ck1 and it really makes a difference. At first I thought the staircase scheduler was responsible for io starvation sometimes, but now this behaviour is gone. Very well! Prakash --------------enig77F5054025E92F7A4470AC2A Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.9.10 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFBbEIzxU2n/+9+t5gRAqv5AJ9MfoJXafImlRQ1t6yMztsyjpWTEACdFDay uttzJTvjENDXkY7ga6MIMdU= =o45H -----END PGP SIGNATURE----- --------------enig77F5054025E92F7A4470AC2A-- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/