From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755010Ab3AJTab (ORCPT ); Thu, 10 Jan 2013 14:30:31 -0500 Received: from moutng.kundenserver.de ([212.227.17.9]:56303 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755009Ab3AJTaa (ORCPT ); Thu, 10 Jan 2013 14:30:30 -0500 Message-ID: <1357846213.5755.30.camel@marge.simpson.net> Subject: Re: [PATCH 0/5] x86,smp: make ticket spinlock proportional backoff w/ auto tuning From: Mike Galbraith To: Rik van Riel Cc: linux-kernel@vger.kernel.org, aquini@redhat.com, walken@google.com, eric.dumazet@gmail.com, lwoodman@redhat.com, jeremy@goop.org, Jan Beulich , knoel@redhat.com, chegu_vinod@hp.com, raghavendra.kt@linux.vnet.ibm.com, mingo@redhat.com Date: Thu, 10 Jan 2013 20:30:13 +0100 In-Reply-To: <50EEDEC1.9020708@redhat.com> References: <20130108172632.1126898a@annuminas.surriel.com> <1357831182.5841.21.camel@marge.simpson.net> <50EEDEC1.9020708@redhat.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 X-Provags-ID: V02:K0:p6ITZCYW61b6J3l2dCjznMBbF9uR5206XV2256vSJag tHEZvDg2At4TAqYbcK7nI7g7qdGQKmgx4pnsW5u+hN1qRknaOE i9sXt0Og1nv+ZUTnh/SJwVjwZbiJbyBDjSvwqm2Mq2KFxOIfDz HxnoHZE04zh0DAFVQWwbyQt6NCfmlwZx0qHpEfHrHlHl59dsP8 9/ofAhWobUOl7nbd/dMBk9j3QpxLZCUZgQjQZhq3k1RbjZmbYg PQ6vBnE793LKzkzkf8C/lu6K1ZfQ+s4ERtpPHyybwaxc5sNuxB qnCeQhEUJlk9LfjN84ddLDtWilozQ6qjQBWiIcLKf1J+37Gjby ATpDBU9pEgXyp26WALz5CD2DDpE+zv++2B9HJfTIeSfELq4W0n EmIyjstcnH6Vg== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2013-01-10 at 10:31 -0500, Rik van Riel wrote: > On 01/10/2013 10:19 AM, Mike Galbraith wrote: > > On Tue, 2013-01-08 at 17:26 -0500, Rik van Riel wrote: > > > >> Please let me know if you manage to break this code in any way, > >> so I can fix it... > > > > I didn't break it, but did let it play with rq->lock contention. Using > > cyclictest -Smp99 -i 100 -d 0, with 3 rt tasks for pull_rt_task() to > > pull around appears to have been a ~dead heat. > > Good to hear that the code seems to be robust. It seems to > help prevent performance degradation in some workloads, and > nobody seems to have found regressions yet. I had hoped for a bit of positive, but a wash isn't surprising given the profile. I tried tbench too, didn't expect to see anything at all there, and got that.. so both results are positive in that respect. -Mike