From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264266AbUEDI2J (ORCPT ); Tue, 4 May 2004 04:28:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264267AbUEDI2J (ORCPT ); Tue, 4 May 2004 04:28:09 -0400 Received: from mx1.redhat.com ([66.187.233.31]:40327 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S264266AbUEDI2G (ORCPT ); Tue, 4 May 2004 04:28:06 -0400 Subject: Re: Random file I/O regressions in 2.6 From: Arjan van de Ven Reply-To: arjanv@redhat.com To: Andrew Morton Cc: Nick Piggin , peter@mysql.com, linuxram@us.ibm.com, alexeyk@mysql.com, linux-kernel@vger.kernel.org, axboe@suse.de In-Reply-To: <20040503171005.1e63a745.akpm@osdl.org> References: <200405022357.59415.alexeyk@mysql.com> <409629A5.8070201@yahoo.com.au> <20040503110854.5abcdc7e.akpm@osdl.org> <1083615727.7949.40.camel@localhost.localdomain> <20040503135719.423ded06.akpm@osdl.org> <1083620245.23042.107.camel@abyss.local> <20040503145922.5a7dee73.akpm@osdl.org> <4096DC89.5020300@yahoo.com.au> <20040503171005.1e63a745.akpm@osdl.org> Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-CPY4T9kMWK9U+02Dlh4/" Organization: Red Hat UK Message-Id: <1083659274.3844.2.camel@laptop.fenrus.com> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.5 (1.4.5-7) Date: Tue, 04 May 2004 10:27:54 +0200 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --=-CPY4T9kMWK9U+02Dlh4/ Content-Type: text/plain Content-Transfer-Encoding: quoted-printable >=20 > That would cause the kernel to perform lots of pointless pagecache lookup= s > when the file is already 100% cached. well surely the read itself will do those AGAIN anyway, so in the fully cached case this is just warming up the cpu cache ;) (and thus really cheap as nett cost I suspect) --=-CPY4T9kMWK9U+02Dlh4/ Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (GNU/Linux) iD8DBQBAl1QKxULwo51rQBIRApreAJ964thZ1kKOIyTedLoJgc/lBMWomgCgm3ts /7GFLtKyBdFZdQoBEdcu2VU= =qK1R -----END PGP SIGNATURE----- --=-CPY4T9kMWK9U+02Dlh4/--