From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751284Ab1DFFE3 (ORCPT ); Wed, 6 Apr 2011 01:04:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:3891 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750738Ab1DFFE2 (ORCPT ); Wed, 6 Apr 2011 01:04:28 -0400 Message-ID: <4D9BF512.6080309@redhat.com> Date: Wed, 06 Apr 2011 01:07:30 -0400 From: Rik van Riel User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.13) Gecko/20101209 Fedora/3.1.7-0.35.b3pre.fc14 Lightning/1.0b3pre Thunderbird/3.1.7 MIME-Version: 1.0 To: Alex Shi CC: linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, mingo@elte.hu, tim.c.chen@intel.com, shaohua.li@intel.com Subject: Re: [PATCH] sched: recover sched_yield task running time increase References: <1302042823-23022-1-git-send-email-alex.shi@intel.com> In-Reply-To: <1302042823-23022-1-git-send-email-alex.shi@intel.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/05/2011 06:33 PM, Alex Shi wrote: > commit ac53db596cc08ecb8040c removed the sched_yield task running > time increase, so the yielded task get more opportunity to be launch > again. That may not the caller want to be. And this also causes > volano benchmark drop 50~80 percent performance on core2/NHM/WSM > machines. This patch recover the sched_yield task vruntime up. > > Signed-off-by: alex.shi@intel.com NACK This was switched off by default and under the sysctl sched_compat_yield for a reason. Reintroducing it under that sysctl option may be acceptable, but by default it would be doing the wrong thing for other workloads.