Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759325Ab1FWMnn (ORCPT ); Thu, 23 Jun 2011 08:43:43 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:45218 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753011Ab1FWMnm (ORCPT ); Thu, 23 Jun 2011 08:43:42 -0400 Date: Thu, 23 Jun 2011 14:43:10 +0200 From: Ingo Molnar To: Peter Zijlstra Cc: Hidetoshi Seto , Paul Turner , linux-kernel@vger.kernel.org, Bharata B Rao , Dhaval Giani , Balbir Singh , Vaidyanathan Srinivasan , Srivatsa Vaddagiri , Kamalesh Babulal , Pavel Emelyanov Subject: Re: [patch 00/16] CFS Bandwidth Control v7 Message-ID: <20110623124310.GA15430@elte.hu> References: <20110621071649.862846205@google.com> <4E01BE6B.2090701@jp.fujitsu.com> <1308830816.1022.112.camel@twins> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1308830816.1022.112.camel@twins> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.3.1 -2.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1271 Lines: 36 * Peter Zijlstra wrote: > On Wed, 2011-06-22 at 19:05 +0900, Hidetoshi Seto wrote: > > > I'll continue my test/benchmark on this v7 for a while. Though I > > believe no more bug is there, I'll let you know if there is > > something. > > Would that testing include performance of a kernel without these > patches vs one with these patches in a configuration where the new > feature is compiled in but not used? > > It does add a number of if (!cfs_rq->runtime_enabled) return > branches all over the place, some possibly inside a function call > (depending on what the auto-inliner does). So while the impact > should be minimal, it would be very good to test it is indeed so. Yeah, doing such performance tests is absolutely required. Branches and instructions impact should be measured as well, beyond the cycles impact. The changelog of this recent commit: c8b281161dfa: sched: Increase SCHED_LOAD_SCALE resolution gives an example of how to do such measurements. Thanks, Ingo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/