From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936607AbXGZWSz (ORCPT ); Thu, 26 Jul 2007 18:18:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S934175AbXGZWSs (ORCPT ); Thu, 26 Jul 2007 18:18:48 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:36908 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762513AbXGZWSs (ORCPT ); Thu, 26 Jul 2007 18:18:48 -0400 Date: Fri, 27 Jul 2007 00:18:30 +0200 From: Ingo Molnar To: "Siddha, Suresh B" Cc: npiggin@suse.de, linux-kernel@vger.kernel.org, akpm@linux-foundation.org Subject: Re: [patch] sched: introduce SD_BALANCE_FORK for ht/mc/smp domains Message-ID: <20070726221830.GA4113@elte.hu> References: <20070726183225.GJ3318@linux-os.sc.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070726183225.GJ3318@linux-os.sc.intel.com> User-Agent: Mutt/1.5.14 (2007-02-12) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.1.7-deb -1.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Siddha, Suresh B wrote: > Introduce SD_BALANCE_FORK for HT/MC/SMP domains. > > For HT/MC, as caches are shared, SD_BALANCE_FORK is the right thing to > do. Given that NUMA domain already has this flag and the scheduler > currently doesn't have the concept of running threads belonging to a > process as close as possible(i.e., forking may keep close, but > periodic balance later will likely take them far away), introduce > SD_BALANCE_FORK for SMP domain too. > > Signed-off-by: Suresh Siddha i'm not opposed to this fundamentally, but it would be nice to better map the effects of this change: do you have any particular workload under which you've tested this and under which you've seen it makes a difference? I'd expect this to improve fork-intense half-idle workloads perhaps - things like a make -j3 on a 4-core CPU. Ingo