From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761503Ab3BOMiY (ORCPT ); Fri, 15 Feb 2013 07:38:24 -0500 Received: from 173-166-109-252-newengland.hfc.comcastbusiness.net ([173.166.109.252]:49644 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754576Ab3BOMiX (ORCPT ); Fri, 15 Feb 2013 07:38:23 -0500 Message-ID: <1360931899.2739.8.camel@laptop> Subject: Re: [patch v4 01/18] sched: set SD_PREFER_SIBLING on MC domain to reduce a domain level From: Peter Zijlstra To: Alex Shi Cc: torvalds@linux-foundation.org, mingo@redhat.com, tglx@linutronix.de, akpm@linux-foundation.org, arjan@linux.intel.com, bp@alien8.de, pjt@google.com, namhyung@kernel.org, efault@gmx.de, vincent.guittot@linaro.org, gregkh@linuxfoundation.org, preeti@linux.vnet.ibm.com, viresh.kumar@linaro.org, linux-kernel@vger.kernel.org Date: Fri, 15 Feb 2013 13:38:19 +0100 In-Reply-To: <511B9392.1080003@intel.com> References: <1358996820-23036-1-git-send-email-alex.shi@intel.com> <1358996820-23036-2-git-send-email-alex.shi@intel.com> <1360663879.4485.2.camel@laptop> <511B9392.1080003@intel.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.6.2-0ubuntu0.1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2013-02-13 at 21:22 +0800, Alex Shi wrote: > No, the flags set on MC/CPU domain, but is checked in their parents > balancing, like in NUMA domain. > Without the flag, will cause NUMA domain imbalance. like on my 2 > sockets > NHM EP: 3 of 4 tasks were assigned on socket 0(lcpu, 10, 12, 14) > > In this case, update_sd_pick_busiest() need a reduced group_capacity > to > return true: > if (sgs->sum_nr_running > sgs->group_capacity) > return true; > then numa domain balancing get chance to start. Ah, indeed. Its always better to include such 'obvious' problems in the changelog :-)