Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761991AbZDCHE4 (ORCPT ); Fri, 3 Apr 2009 03:04:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755119AbZDCHEr (ORCPT ); Fri, 3 Apr 2009 03:04:47 -0400 Received: from one.firstfloor.org ([213.235.205.2]:43554 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754002AbZDCHEq (ORCPT ); Fri, 3 Apr 2009 03:04:46 -0400 To: Gautham R Shenoy Cc: "Ingo Molnar" , Peter Zijlstra , Vaidyanathan Srinivasan , linux-kernel@vger.kernel.org, Suresh Siddha , "Balbir Singh" Subject: Re: [PATCH v2 1/2] sched: Nominate idle load balancer from a semi-idle package. From: Andi Kleen References: <20090402123607.14569.33649.stgit@sofia.in.ibm.com> <20090402123829.14569.67639.stgit@sofia.in.ibm.com> Date: Fri, 03 Apr 2009 09:04:42 +0200 In-Reply-To: <20090402123829.14569.67639.stgit@sofia.in.ibm.com> (Gautham R. Shenoy's message of "Thu, 02 Apr 2009 18:08:29 +0530") Message-ID: <87hc16kyk5.fsf@basil.nowhere.org> User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/22.3 (gnu/linux) 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 Content-Length: 1012 Lines: 28 Gautham R Shenoy writes: > > Improve the algorithm to nominate the idle load balancer from a semi idle > cores/packages thereby increasing the probability of the cores/packages being > in deeper sleep states for longer duration. The basic patch looks good. In theory you could also look for a nearby nohz balancer in the end to optimize traffic on the interconnect of a larger NUMA system, but it's probably not worth it. > > The algorithm is activated only when sched_mc/smt_power_savings != 0. But it seems to me that this check could be dropped and doing it unconditionally, because idle balancing doesn't need much memory bandwith or cpu power, so always putting it nearby is good. -Ani -- ak@linux.intel.com -- Speaking for myself only. -- 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/