From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932364Ab2EIUjc (ORCPT ); Wed, 9 May 2012 16:39:32 -0400 Received: from casper.infradead.org ([85.118.1.10]:44105 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932347Ab2EIUj3 convert rfc822-to-8bit (ORCPT ); Wed, 9 May 2012 16:39:29 -0400 Message-ID: <1336595963.2527.69.camel@twins> Subject: Re: [tip:sched/core] sched/fair: Let minimally loaded cpu balance the group From: Peter Zijlstra To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, tglx@linutronix.de Cc: linux-tip-commits@vger.kernel.org Date: Wed, 09 May 2012 22:39:23 +0200 In-Reply-To: References: Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT X-Mailer: Evolution 3.2.2- Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2012-05-09 at 07:26 -0700, tip-bot for Peter Zijlstra wrote: > sched/fair: Let minimally loaded cpu balance the group > > Currently we let the leftmost (or first idle) cpu ascend the > sched_domain tree and perform load-balancing. The result is that the > busiest cpu in the group might be performing this function and pull > more load to itself. The next load balance pass will then try to > equalize this again. > > Change this to pick the least loaded cpu to perform higher domain > balancing. OK, so while this all sounds great its horrible broken.. there's no guarantee the selected cpu actually gets to balance the domain for it might never reach as high in its own balance pass since by then it might not be the least loaded anymore. Will have to poke at this more tomorrow, but from what my tired brain makes of it there's nothing but a straight revert (and probably similar for the next patch).