Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754859AbYCYOIk (ORCPT ); Tue, 25 Mar 2008 10:08:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750829AbYCYOId (ORCPT ); Tue, 25 Mar 2008 10:08:33 -0400 Received: from os.eurotux.com ([216.75.63.6]:36247 "EHLO os.eurotux.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750727AbYCYOIc (ORCPT ); Tue, 25 Mar 2008 10:08:32 -0400 Date: Tue, 25 Mar 2008 14:08:25 +0000 From: Luciano Rocha To: Michael Meyer Cc: linux-kernel@vger.kernel.org Subject: Re: performance differences: "maxcpus=1" vs. "echo 0 > /sys/devices/system/cpu/cpu1/online" Message-ID: <20080325140825.GA19722@bit.office.eurotux.com> Mail-Followup-To: Luciano Rocha , Michael Meyer , linux-kernel@vger.kernel.org References: <16336.23884.qm@web25814.mail.ukl.yahoo.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="7JfCtLOvnd9MIVvH" Content-Disposition: inline In-Reply-To: <16336.23884.qm@web25814.mail.ukl.yahoo.com> User-Agent: Mutt/1.5.14 (2007-03-31) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1156 Lines: 40 --7JfCtLOvnd9MIVvH Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Mar 25, 2008 at 02:47:50PM +0100, Michael Meyer wrote: > Hi,=20 >=20 > what is the difference between booting a dual core > machine with "maxcpus=3D1" or by deactivating the second > core at run time with "echo 0 > > /sys/devices/system/cpu/cpu1/online"? maxcpus=3D1 should turn off the SMP alternative and switch to UP only, optimising some locks and instructions. --=20 Luciano Rocha Eurotux Inform=E1tica, S.A. --7JfCtLOvnd9MIVvH Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (GNU/Linux) iD8DBQFH6QdZinSul6a7oB8RAkOuAJ4oQv3IWvYoF/GHo+rgdj316/GGJACeJJpf 6VoLYTU5274kExEEtB3dl5k= =u8LD -----END PGP SIGNATURE----- --7JfCtLOvnd9MIVvH-- -- 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/