From owner-freebsd-hackers@FreeBSD.ORG Mon Nov 26 08:59:48 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 3866016A419 for ; Mon, 26 Nov 2007 08:59:48 +0000 (UTC) (envelope-from jbucht@gmail.com) Received: from rv-out-0910.google.com (rv-out-0910.google.com [209.85.198.189]) by mx1.freebsd.org (Postfix) with ESMTP id 08F4A13C4D9 for ; Mon, 26 Nov 2007 08:59:47 +0000 (UTC) (envelope-from jbucht@gmail.com) Received: by rv-out-0910.google.com with SMTP id l15so479820rvb for ; Mon, 26 Nov 2007 00:59:47 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; bh=Y+0hzaTtMxiEeA2bHvBNz4A8Qf3Ugz83jHI4thbFzZk=; b=dCKDKEEJclPrfnBpJkMhASuNf2DkN+lk/2VYUkYQhZNP0phX9IGke+7Wn43oXmx65qMvExAuKr49CdLlMkp3FHNKySKw9dk3J8VEWRzJNI+goZS9jTGbkU0T2KCYf7+DM6L1HU7rMBuq14TS43+dmcqGQQMHQavqD6dCum0S6Qg= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=AATacjtQ3PCRC69IgjEP2WfZPKTBc+y83oFXQTX7kJD/gLKTvI03NwuPk2Y/fSYZ3NhKrJ6UnR4d0sd2P/o1IfIqUha8P8A2rKqsao1O1jAKuO8Ghxzl06TjkinI8zvuExBCJXy5LYY+oN0iipRKoas4mB8vg8eRjvg42porxPI= Received: by 10.140.180.42 with SMTP id c42mr983045rvf.1196065874118; Mon, 26 Nov 2007 00:31:14 -0800 (PST) Received: by 10.140.193.13 with HTTP; Mon, 26 Nov 2007 00:31:14 -0800 (PST) Message-ID: <947010c30711260031w10689412w5f5ce56abc1fbe56@mail.gmail.com> Date: Mon, 26 Nov 2007 09:31:14 +0100 From: "Johan Bucht" To: "Stephen Montgomery-Smith" In-Reply-To: <20071125143546.V6583@cauchy.math.missouri.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline 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> <20071125143546.V6583@cauchy.math.missouri.edu> Cc: binto , freebsd-hackers@freebsd.org, Robert Watson , 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: Mon, 26 Nov 2007 08:59:48 -0000 2007/11/25, Stephen Montgomery-Smith : > > > 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! Actually, some worksets can get a higher speedup since you usually double your cache size going from one to two cpus (core 2 duo has a shared cache). Should the problem be big enough not to fit in one cpu's cache but small enough to fit in two cpu's caches, you can get more than 2 times speedup. /Johan