From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754266Ab0KTQby (ORCPT ); Sat, 20 Nov 2010 11:31:54 -0500 Received: from mail-qw0-f46.google.com ([209.85.216.46]:46701 "EHLO mail-qw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752430Ab0KTQbw (ORCPT ); Sat, 20 Nov 2010 11:31:52 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=from:to:cc:subject:in-reply-to:references:user-agent:date :message-id:mime-version:content-type; b=d5YD3V3ssCbLpNsEhqtePUkM5yFkUyVdiLPAzpFb0N32qeHkqV3gji3WSQL1it/qyK A7vL9VhOLV/5ULv6HMUz/ZC1P2JngY14Qp927qRJaZ3qfGLr9twae0qo3M99HFJAj1K3 pqNn8v1N4uLWsAwV/AMcu3ivavY1+HWpNJkak= From: Ben Gamari To: Suresh Siddha , "H. Peter Anvin" , Ingo Molnar , Thomas Gleixner Cc: LKML , Arjan van de Ven Subject: Re: [patch] x86: avoid unnecessary smp alternatives switch during suspend/resume In-Reply-To: <1290211764.2637.8.camel@sbsiddha-MOBL3.sc.intel.com> References: <1290211764.2637.8.camel@sbsiddha-MOBL3.sc.intel.com> User-Agent: Notmuch/0.5-3-g22aadfc (http://notmuchmail.org) Emacs/23.1.1 (x86_64-pc-linux-gnu) Date: Sat, 20 Nov 2010 11:31:46 -0500 Message-ID: <87tyjcj6rx.fsf@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 19 Nov 2010 16:09:24 -0800, Suresh Siddha wrote: > During suspend, we disable all the non boot cpus. And during resume we bring > them all back again. So no need to do alternatives_smp_switch() in between. > > This speeds up both suspend and resume paths. > Do you have typical before/after values? Is the change on the order of microseconds, hundreds of milliseconds, or somewhere in between? It might be good to note this in the changelog. - Ben