From owner-freebsd-current@FreeBSD.ORG Tue Feb 7 22:43:23 2006 Return-Path: <owner-freebsd-current@FreeBSD.ORG> X-Original-To: freebsd-current@freebsd.org Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2C62516A422; Tue, 7 Feb 2006 22:43:23 +0000 (GMT) (envelope-from jhb@freebsd.org) Received: from speedfactory.net (mail6.speedfactory.net [66.23.216.219]) by mx1.FreeBSD.org (Postfix) with ESMTP id 602E443D48; Tue, 7 Feb 2006 22:43:21 +0000 (GMT) (envelope-from jhb@freebsd.org) Received: from server.baldwin.cx (unverified [66.23.211.162]) by speedfactory.net (SurgeMail 3.5b3) with ESMTP id 7963647 for multiple; Tue, 07 Feb 2006 17:42:59 -0500 Received: from localhost (john@localhost [127.0.0.1]) by server.baldwin.cx (8.13.4/8.13.4) with ESMTP id k17Mh70T052129; Tue, 7 Feb 2006 17:43:07 -0500 (EST) (envelope-from jhb@freebsd.org) From: John Baldwin <jhb@freebsd.org> To: Andrew Gallatin <gallatin@cs.duke.edu> Date: Tue, 7 Feb 2006 17:30:51 -0500 User-Agent: KMail/1.9.1 References: <17379.56708.421007.613310@grasshopper.cs.duke.edu> <200602071037.05314.jhb@freebsd.org> <17385.7187.845964.182297@grasshopper.cs.duke.edu> In-Reply-To: <17385.7187.845964.182297@grasshopper.cs.duke.edu> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200602071730.53881.jhb@freebsd.org> X-Virus-Scanned: ClamAV 0.87.1/1280/Tue Feb 7 05:11:53 2006 on server.baldwin.cx X-Virus-Status: Clean X-Spam-Status: No, score=-1.4 required=4.2 tests=ALL_TRUSTED autolearn=failed version=3.1.0 X-Spam-Checker-Version: SpamAssassin 3.1.0 (2005-09-13) on server.baldwin.cx X-Server: High Performance Mail Server - http://surgemail.com r=1653887525 Cc: freebsd-current@freebsd.org, Andre Oppermann <andre@freebsd.org> Subject: Re: machdep.cpu_idle_hlt and SMP perf? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current <freebsd-current.freebsd.org> List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>, <mailto:freebsd-current-request@freebsd.org?subject=unsubscribe> List-Archive: <http://lists.freebsd.org/pipermail/freebsd-current> List-Post: <mailto:freebsd-current@freebsd.org> List-Help: <mailto:freebsd-current-request@freebsd.org?subject=help> List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-current>, <mailto:freebsd-current-request@freebsd.org?subject=subscribe> X-List-Received-Date: Tue, 07 Feb 2006 22:43:23 -0000 On Tuesday 07 February 2006 17:15, Andrew Gallatin wrote: > John Baldwin writes: > > On Monday 06 February 2006 17:37, Andrew Gallatin wrote: > > > John Baldwin writes: > > > > On Monday 06 February 2006 14:46, Andrew Gallatin wrote: > > > > > Andre Oppermann writes: > > > > > > Andrew Gallatin wrote: > > > > > > > Why dooes machdep.cpu_idle_hlt=1 drop my 10GbE network rx > > > > > > > performance by a considerable amount (7.5Gbs -> 5.5Gbs)? > > > > > > > > You may be seeing problems because it might simply take a while for > > > > the CPU to wake up from HLT when an interrupt comes in. The 4BSD > > > > scheduler tries to do IPIs to wakeup any sleeping CPUs when it > > > > schedules a new thread, but that would add higher latency for > > > > ithreads than just preempting directly to the ithread. Oh, you > > > > have to turn that on, it's off by default > > > > (kern.sched.ipiwakeup.enabled=1). > > > > > > Hmm.. It seems to be on by default. Unfortunately, it does not seem > > > to help. > > > > I'm not sure. > > One thing which really helps is disabling preemption. If I do that, > I get 7.7Gb/sec with machdep.cpu_idle_hlt=1. This is slightly better > than machdep.cpu_idle_hlt=0 and no PREEMPTION. > > BTW, net.isr.direct=1 in all testing. Do you have very little userland activity in this test? -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org