From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756282AbZBTT5s (ORCPT ); Fri, 20 Feb 2009 14:57:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753251AbZBTT5l (ORCPT ); Fri, 20 Feb 2009 14:57:41 -0500 Received: from casper.infradead.org ([85.118.1.10]:40045 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753281AbZBTT5k (ORCPT ); Fri, 20 Feb 2009 14:57:40 -0500 Date: Fri, 20 Feb 2009 11:57:45 -0800 From: Arjan van de Ven To: Ingo Molnar Cc: Vaidyanathan Srinivasan , linux-kernel@vger.kernel.org, linux-pm@lists.linux-foundation.org, a.p.zijlstra@chello.nl, ego@in.ibm.com, tglx@linutronix.de, andi@firstfloor.org, venkatesh.pallipadi@intel.com, vatsa@linux.vnet.ibm.com, arun@linux.vnet.ibm.com, Suresh Siddha Subject: Re: [RFC PATCH 0/4] timers: framework for migration between CPU Message-ID: <20090220115745.43d202d6@infradead.org> In-Reply-To: <20090220160737.GC11294@elte.hu> References: <20090220125516.GB10232@linux.vnet.ibm.com> <20090220132145.GF26418@elte.hu> <20090220141415.GA27381@dirshya.in.ibm.com> <20090220160737.GC11294@elte.hu> Organization: Intel X-Mailer: Claws Mail 3.7.0 (GTK+ 2.14.7; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 20 Feb 2009 17:07:37 +0100 Ingo Molnar wrote: > > * Vaidyanathan Srinivasan wrote: > > > > I'd also suggest to not do that rather ugly > > > enable_timer_migration per-cpu variable, but simply reuse > > > the existing nohz.load_balancer as a target CPU. > > > > This is a good idea to automatically bias the timers. But > > this nohz.load_balancer is a very fast moving target and we > > will need some heuristics to estimate overall system idleness > > before moving the timers. > > > > I would agree that the power saving load balancer has a good > > view of the system and can potentially guide the timer biasing > > framework. > > Yeah, it's a fast moving target, but it already concentrates > the load somewhat. > I wonder if the real answer for this isn't to have timers be considered schedulable-entities and have the regular scheduler decide where they actually run. -- Arjan van de Ven Intel Open Source Technology Centre For development, discussion and tips for power savings, visit http://www.lesswatts.org