From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932306AbVHNVYh (ORCPT ); Sun, 14 Aug 2005 17:24:37 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932308AbVHNVYh (ORCPT ); Sun, 14 Aug 2005 17:24:37 -0400 Received: from mxfep02.bredband.com ([195.54.107.73]:16264 "EHLO mxfep02.bredband.com") by vger.kernel.org with ESMTP id S932306AbVHNVYh (ORCPT ); Sun, 14 Aug 2005 17:24:37 -0400 Subject: Re: [RFC] [PATCH] cache pollution aware __copy_from_user_ll() From: Ian Kumlien Reply-To: pomac@vapor.com To: linux-kernel@vger.kernel.org Cc: hch@infradead.org, arian@infradead.org, lkml.hyoshiok@gmail.com Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="=-+WHVD58LyIKj5Djda9+x" Date: Sun, 14 Aug 2005 23:24:20 +0200 Message-Id: <1124054660.10376.15.camel@localhost> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --=-+WHVD58LyIKj5Djda9+x Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Hi, all I might be missunderstanding things but... First of all, machines with long pipelines will suffer from cache misses (p4 in this case). Depending on the size copied, (i don't know how large they are so..) can't one run out of cachelines and/or evict more useful cache data? Ie, if it's cached from begining to end, we generally only need 'some of' the begining, the cpu's prefetch should manage the rest. I might, as i said, not know all about things like this and i also suffer from a fever but i still find Hiro's data interesting. Isn't there some way to do the same test for the same time and measure the differences in allround data? to see if we really are punished as bad on accessing the data post copy? (could it be size dependant?) --=20 Ian Kumlien -- http://pomac.netswarm.net --=-+WHVD58LyIKj5Djda9+x Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.1-ecc0.1.6 (GNU/Linux) iD8DBQBC/7aE7F3Euyc51N8RAjP+AJ9x36doGPtrF7WWZI0S/AaZSENtuwCfYocP tMyQR5vpD06u+Stzxl6jicY= =Ppx9 -----END PGP SIGNATURE----- --=-+WHVD58LyIKj5Djda9+x--