From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751707AbWLMWpw (ORCPT ); Wed, 13 Dec 2006 17:45:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751709AbWLMWpw (ORCPT ); Wed, 13 Dec 2006 17:45:52 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:58738 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751704AbWLMWpw (ORCPT ); Wed, 13 Dec 2006 17:45:52 -0500 Date: Wed, 13 Dec 2006 23:43:17 +0100 From: Ingo Molnar To: "Siddha, Suresh B" Cc: nickpiggin@yahoo.com.au, vatsa@in.ibm.com, clameter@sgi.com, tglx@linutronix.de, arjan@linux.intel.com, linux-kernel@vger.kernel.org Subject: Re: [RFC] Patch: dynticks: idle load balancing Message-ID: <20061213224317.GA2986@elte.hu> References: <20061211155304.A31760@unix-os.sc.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20061211155304.A31760@unix-os.sc.intel.com> User-Agent: Mutt/1.4.2.2i X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -5.9 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-5.9 required=5.9 tests=ALL_TRUSTED,BAYES_00 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts -2.6 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: > Appended patch attempts to fix the process idle load balancing in the > presence of dynticks. cpus for which ticks are stopped will sleep till > the next event wakes it up. Potentially these sleeps can be for large > durations and during which today, there is no idle load balancing > being done. There was some discussion happened(last year) on this > topic on lkml, where two main approaches were gettting debated. One is > to back off the idle load balancing for bigger intervals and the > second is a watchdog mechanism where the busy cpu will trigger the > load balance on an idle cpu. Both of these mechanisms have its > drawbacks. nice work! I have added your patch to -rt. Btw., it needs the patch below to work on 64-bit. Ingo Index: linux/kernel/sched.c =================================================================== --- linux.orig/kernel/sched.c +++ linux/kernel/sched.c @@ -1170,7 +1170,7 @@ static void resched_task(struct task_str static void resched_cpu(int cpu) { struct rq *rq = cpu_rq(cpu); - unsigned int flags; + unsigned long flags; spin_lock_irqsave(&rq->lock, flags); resched_task(cpu_curr(cpu));