From owner-freebsd-performance@FreeBSD.ORG Wed Oct 24 15:50:46 2007 Return-Path: Delivered-To: freebsd-performance@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 0C72416A419; Wed, 24 Oct 2007 15:50:46 +0000 (UTC) (envelope-from nevans@talkpoint.com) Received: from mailbox.talkpoint.com (mailbox.talkpoint.com [204.141.15.162]) by mx1.freebsd.org (Postfix) with ESMTP id CD38013C465; Wed, 24 Oct 2007 15:50:45 +0000 (UTC) (envelope-from nevans@talkpoint.com) Received: from localhost (localhost [127.0.0.1]) by mailbox.talkpoint.com (Postfix) with ESMTP id A1BEF458009; Wed, 24 Oct 2007 11:50:38 -0400 (EDT) X-Virus-Scanned: amavisd-new at X-Spam-Flag: NO X-Spam-Score: -2.431 X-Spam-Level: X-Spam-Status: No, score=-2.431 tagged_above=-10 required=5 tests=[AWL=0.168, BAYES_00=-2.599] Received: from mailbox.talkpoint.com ([127.0.0.1]) by localhost (mailbox.talkpoint.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id FfJFLgcZ+-df; Wed, 24 Oct 2007 11:50:35 -0400 (EDT) Received: from pleiades.nextvenue.com (pleiades.nextvenue.com [204.141.15.194]) by mailbox.talkpoint.com (Postfix) with ESMTP id 7252A458001; Wed, 24 Oct 2007 11:50:35 -0400 (EDT) Date: Wed, 24 Oct 2007 11:49:54 -0400 From: Nick Evans To: josh.carroll@gmail.com Message-ID: <20071024114954.5ea1b37b@pleiades.nextvenue.com> In-Reply-To: <8cb6106e0710240839h1a59f9f9y919e6b297c3efb8e@mail.gmail.com> References: <8cb6106e0710230902x4edf2c8eu2d912d5de1f5d4a2@mail.gmail.com> <471E343C.2040509@FreeBSD.org> <20071024171915.E84143@delplex.bde.org> <8cb6106e0710240639r20e03ce9w81ed3354338b7395@mail.gmail.com> <20071024113434.326c3749@pleiades.nextvenue.com> <8cb6106e0710240839h1a59f9f9y919e6b297c3efb8e@mail.gmail.com> X-Mailer: Claws Mail 2.8.0 (GTK+ 2.10.9; i386-portbld-freebsd7.0) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: remy.nonnenmacher@activnetworks.com, Kris Kennaway , freebsd-performance@freebsd.org, Bruce Evans Subject: Re: ULE vs. 4BSD in RELENG_7 X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 24 Oct 2007 15:50:46 -0000 On Wed, 24 Oct 2007 11:39:52 -0400 "Josh Carroll" wrote: > > kern.sched.steal_thresh is/was one of the more effective tuning sysctls. > > rev 1.205 of sched_ule had a change that was supposed to automatically > > adjust it based on the number of cores. Is this the same 8 core system as > > the other thread? In that case the commit dictates steal_thresh should be > > set to 3. Give that a try. > > This is a quad core (single cpu) system. Do these values look proper then? > > kern.sched.steal_thresh: 2 > kern.sched.steal_idle: 1 > kern.sched.steal_htt: 1 > > Thanks, > Josh Yes, that's the proper default. You could try setting steal_thresh to 1. I noticed a problem with building ports on an 8 core Xeon system while 8 distributed.net crunchers were running. The port build would proceed incredibly slowly, steal_thresh=1 helped a little bit. It might not make up the 5% gap you're seeing though. During early ULE2/3 testing the other variables Jeff recommended trying were sched.pick_pri (which I never saw effect from), sched_tryself and sched.balance. They're all bools IIRC. Since this workload is a bit different from any of mine it would be worthwhile to try those variables. Nick