Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752118Ab0FDGW6 (ORCPT ); Fri, 4 Jun 2010 02:22:58 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:35768 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750775Ab0FDGW4 (ORCPT ); Fri, 4 Jun 2010 02:22:56 -0400 Date: Fri, 4 Jun 2010 08:22:21 +0200 From: Ingo Molnar To: Linus Torvalds Cc: tytso@mit.edu, Brian Swetland , Neil Brown , Arve Hj?nnev?g , Thomas Gleixner , "Rafael J. Wysocki" , Alan Stern , Felipe Balbi , Peter Zijlstra , LKML , Florian Mickler , Linux OMAP Mailing List , Linux PM , Alan Cox , James Bottomley , Peter Zijlstra , Kevin Hilman , "H. Peter Anvin" , Arjan van de Ven Subject: Re: suspend blockers & Android integration Message-ID: <20100604062221.GA32136@elte.hu> References: <20100603193045.GA7188@elte.hu> <20100603231153.GA11302@elte.hu> <20100603232302.GA16184@elte.hu> <20100603234634.GA21831@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0002] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1116 Lines: 26 * Linus Torvalds wrote: > [...] > > And those two things go together. The /sys/power/state thing is a global > suspend - which I don't think is appropriate for a opportunistic thing in > the first place, especially for multi-core. > > A well-designed opportunistic suspend should be a two-phase thing: an > opportunistc CPU hotunplug (shutting down cores one by one as the system is > idle), and not a "global" event in the first place. And only when you've > reached single-core state should you then say "do I suspend the system too". Shutting a core down would be a natural idle level, and when the last one goes idle we can do the suspend. (it happens as part of suspend anyway) So on systems that dont want to auto-suspend this would indeed behave like you suggest: the final core left would run as UP in essence. Ingo -- 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/