From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752316AbbCZKzy (ORCPT ); Thu, 26 Mar 2015 06:55:54 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:41551 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751325AbbCZKzx (ORCPT ); Thu, 26 Mar 2015 06:55:53 -0400 Date: Thu, 26 Mar 2015 11:55:34 +0100 From: Peter Zijlstra To: Vincent Guittot Cc: mingo@kernel.org, linux-kernel@vger.kernel.org, preeti@linux.vnet.ibm.com, Morten.Rasmussen@arm.com, kamalesh@linux.vnet.ibm.com, riel@redhat.com, efault@gmx.de, nicolas.pitre@linaro.org, dietmar.eggemann@arm.com, linaro-kernel@lists.linaro.org Subject: Re: [PATCH v10 10/11] sched: add SD_PREFER_SIBLING for SMT level Message-ID: <20150326105534.GX21418@twins.programming.kicks-ass.net> References: <1425052454-25797-1-git-send-email-vincent.guittot@linaro.org> <1425052454-25797-11-git-send-email-vincent.guittot@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1425052454-25797-11-git-send-email-vincent.guittot@linaro.org> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Feb 27, 2015 at 04:54:13PM +0100, Vincent Guittot wrote: > Add the SD_PREFER_SIBLING flag for SMT level in order to ensure that > the scheduler will put at least 1 task per core. > > Signed-off-by: Vincent Guittot > Reviewed-by: Preeti U. Murthy Preeti, what benchmarks did you use on power8 smt to verify performance? I'm seeing a slight but statistically significant regression on my ivb-ep kernel build when I match the build concurrency to my core count. /me goes run (and install, its a fairly new box) more benches.