From owner-freebsd-hackers@FreeBSD.ORG Sun Nov 25 21:01:48 2007 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id B770316A41A; Sun, 25 Nov 2007 21:01:47 +0000 (UTC) (envelope-from stephen@math.missouri.edu) Received: from cauchy.math.missouri.edu (cauchy.math.missouri.edu [128.206.184.213]) by mx1.freebsd.org (Postfix) with ESMTP id 7F8F613C4DB; Sun, 25 Nov 2007 21:01:47 +0000 (UTC) (envelope-from stephen@math.missouri.edu) Received: from cauchy.math.missouri.edu (localhost [127.0.0.1]) by cauchy.math.missouri.edu (8.14.2/8.14.1) with ESMTP id lAPKfa5P006610; Sun, 25 Nov 2007 14:41:36 -0600 (CST) (envelope-from stephen@math.missouri.edu) Received: from localhost (redmail@localhost) by cauchy.math.missouri.edu (8.14.2/8.14.1/Submit) with ESMTP id lAPKfZa0006607; Sun, 25 Nov 2007 14:41:35 -0600 (CST) (envelope-from stephen@math.missouri.edu) X-Authentication-Warning: cauchy.math.missouri.edu: redmail owned process doing -bs Date: Sun, 25 Nov 2007 14:41:35 -0600 (CST) From: Stephen Montgomery-Smith X-X-Sender: redmail@cauchy.math.missouri.edu To: Robert Watson In-Reply-To: <20071125110116.U63238@fledge.watson.org> Message-ID: <20071125143546.V6583@cauchy.math.missouri.edu> References: <474830F9.90305@zirakzigil.org> <6eb82e0711240638g2cc1e54o1fb1321cafe8ff9f@mail.gmail.com> <1188.202.127.99.4.1195957922.squirrel@webmail.triplegate.net.id> <20071125110116.U63238@fledge.watson.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: binto , freebsd-hackers@freebsd.org, Girwatson@freebsd.org Subject: Re: Before & After Under The Giant Lock X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 25 Nov 2007 21:01:48 -0000 On Sun, 25 Nov 2007, Robert Watson wrote: > ........................ > In FreeBSD 8, I expect we'll see a continued focus on both locking > granularity and improving opportunities for kernel parallelism by better > distributing workloads over CPU pools. This is important because the number > of cores/chip is continuing to increase dramatically, so MP performance is > going to be important to keep working on. That said, the results to date > have been extremely promising, and I anticipate that we will continue to find > ways to better exploit multiprocessor hardware, especially in the network > stack. > I just want to add my 2 cents, that my recent experience with FreeBSD MP has been extremely positive. I tend to use highly CPU bound MP programs, typically lots and lots of floating point operations. It used to be that Linux beat FreeBSD hands down - now FreeBSD seems to have a slight edge! Basically my program runs about twice as fast when I run two threads as opposed to one - I cannot see doing any better than that! (Also when I run 4 threads with 2 cpus, each with hyperthreading, it goes 2.5 to 3 times faster - surprising since hyperthreading gets quite bad press for its performance improvements - I should add that Linux didn't do at all well at taking advantage of hyperthreading, running at the same speed as with 2 threads.) Stephen