Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754245AbXIRIsm (ORCPT ); Tue, 18 Sep 2007 04:48:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752079AbXIRIsf (ORCPT ); Tue, 18 Sep 2007 04:48:35 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:51342 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752067AbXIRIse (ORCPT ); Tue, 18 Sep 2007 04:48:34 -0400 Date: Tue, 18 Sep 2007 10:48:25 +0200 From: Ingo Molnar To: Rob Hussey Cc: linux-kernel@vger.kernel.org, ck@vds.kolivas.org Subject: Re: Scheduler benchmarks - a follow-up Message-ID: <20070918084825.GA25803@elte.hu> References: <6b8cef970709170221s4301e896x2ee123a149c05c3a@mail.gmail.com> <20070917130524.GA10707@elte.hu> <20070917203607.GA20564@elte.hu> <6b8cef970709172130v317a6c48h814ef5a1488f798e@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <6b8cef970709172130v317a6c48h814ef5a1488f798e@mail.gmail.com> User-Agent: Mutt/1.5.14 (2007-02-12) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.1.7-deb -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1636 Lines: 33 * Rob Hussey wrote: > The obligatory graphs: > http://www.healthcarelinen.com/misc/benchmarks/BOUND_NOPREEMPT_lat_ctx_benchmark.png > http://www.healthcarelinen.com/misc/benchmarks/BOUND_NOPREEMPT_hackbench_benchmark.png > http://www.healthcarelinen.com/misc/benchmarks/BOUND_NOPREEMPT_pipe-test_benchmark.png btw., it's likely that if you turn off CONFIG_PREEMPT for .21 and for .22-ck1 they'll improve a bit too - so it's not fair to put the .23 !PREEMPT numbers on the graph as the PREEMPT numbers of the other kernels. (it shows the .23 scheduler being faster than it really is) > A cursory glance suggests that performance wrt lat_ctx and hackbench > has increased (lower numbers), but degraded quite a lot for pipe-test. > The numbers for pipe-test are extremely stable though, while the > numbers for hackbench are more erratic (which isn't saying much since > the original numbers gave nearly a straight line). I'm still willing > to try out any more ideas. the pipe-test behavior looks like an outlier. !PREEMPT only removes code (which makes the code faster), so this could be a cache layout artifact. (or perhaps we preempt at a different point which is disadvantageous to caching?) Pipe-test is equivalent to "lat_ctx -s 0 2" so if there was a genuine slowdown it would show up in the lat_ctx graph - but the graph shows a speedup. 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/