From owner-freebsd-current@FreeBSD.ORG Mon Feb 13 15:42:16 2006 Return-Path: X-Original-To: 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 95A3716A420; Mon, 13 Feb 2006 15:42:16 +0000 (GMT) (envelope-from gallatin@cs.duke.edu) Received: from duke.cs.duke.edu (duke.cs.duke.edu [152.3.140.1]) by mx1.FreeBSD.org (Postfix) with ESMTP id 0F1A643D80; Mon, 13 Feb 2006 15:42:11 +0000 (GMT) (envelope-from gallatin@cs.duke.edu) Received: from grasshopper.cs.duke.edu (grasshopper.cs.duke.edu [152.3.145.30]) by duke.cs.duke.edu (8.13.4/8.13.4) with ESMTP id k1DFgB2f009772 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Mon, 13 Feb 2006 10:42:11 -0500 (EST) Received: (from gallatin@localhost) by grasshopper.cs.duke.edu (8.12.9p2/8.12.9/Submit) id k1DFg4Cq047406; Mon, 13 Feb 2006 10:42:04 -0500 (EST) (envelope-from gallatin) From: Andrew Gallatin MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <17392.43212.367624.807423@grasshopper.cs.duke.edu> Date: Mon, 13 Feb 2006 10:42:04 -0500 (EST) To: Robert Watson In-Reply-To: <20060211005438.E90460@fledge.watson.org> References: <17388.44976.250463.383429@grasshopper.cs.duke.edu> <5383.1139586916@critter.freebsd.dk> <17388.60202.862312.337026@grasshopper.cs.duke.edu> <20060211005438.E90460@fledge.watson.org> X-Mailer: VM 6.75 under 21.1 (patch 12) "Channel Islands" XEmacs Lucid Cc: Poul-Henning Kamp , current@FreeBSD.org Subject: Re: [TEST/REVIEW] cpu time accounting patch, step 2 X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 13 Feb 2006 15:42:16 -0000 Robert Watson writes: > > On Fri, 10 Feb 2006, Andrew Gallatin wrote: > > > Unfortunately, even after your patch, we are still about 38% slower than > > linux x86_64 on the same box for loopback ping-pong, and 32% slower for > > ping-pong over 10GbE. (bandwidth is lower for streaming tests, and CPU > > utilization is much, much much higher in FreeBSD as well). > > > > I think you nailed the biggest source of overhead, but there is apparently a > > lot more performance that we can get out of the hardware. I'd love to see > > you commit this. > > I can't remember if I pointed you at this before, but I remember us talking > about it by e-mail. What happens to your loopback performance if you compile > PREEMPTION out of the kernel? As long as I have machdep.cpu_idle_hlt=0 and am using the BSD scheduler, disabling preemption does not help. If I do disable preemption, then I can also enable machdep.cpu_idle_hlt without a penalty. Drew