From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932760AbWAKBaL (ORCPT ); Tue, 10 Jan 2006 20:30:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932761AbWAKBaL (ORCPT ); Tue, 10 Jan 2006 20:30:11 -0500 Received: from smtp.osdl.org ([65.172.181.4]:51338 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S932760AbWAKBaK (ORCPT ); Tue, 10 Jan 2006 20:30:10 -0500 Date: Tue, 10 Jan 2006 17:31:59 -0800 From: Andrew Morton To: Martin Bligh Cc: linux-kernel@vger.kernel.org, Ingo Molnar Subject: Re: -mm seems significanty slower than mainline on kernbench Message-Id: <20060110173159.55cce659.akpm@osdl.org> In-Reply-To: <43C45BDC.1050402@google.com> References: <43C45BDC.1050402@google.com> X-Mailer: Sylpheed version 1.0.0 (GTK+ 1.2.10; i386-vine-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Martin Bligh wrote: > > OK, I fixed the graphs so you can actually read them now ;-) They're cute. > http://test.kernel.org/perf/kernbench.elm3b6.png (x86_64 4x) > http://test.kernel.org/perf/kernbench.moe.png (NUMA-Q) > http://test.kernel.org/perf/kernbench.elm3b132.png (4x SMP ia32) > > Both seems significantly slower on -mm (mm is green line) Well, 1% slower. -mm has permanent not-for-linus debug things, some of which are expected to have a performance impact. I don't know whether they'd have a 1% impact though. > If I look at diffprofile between 2.6.15 and 2.6.15-mm1, it just looks > like we have lots more idle time. Yes, we do. It'd be useful to test -git7.. > You got strange scheduler changes in > there, that you've been carrying for a long time (2.6.14-mm1 at least)? > or HZ piddling? See to be mainly getting much more idle time. Yes, there are CPU scheduler changes, although much fewer than usual. Ingo, any suggestions as to a culprit?