From owner-freebsd-hackers@FreeBSD.ORG Mon Nov 26 01:15:14 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 1C55416A46B for ; Mon, 26 Nov 2007 01:15:14 +0000 (UTC) (envelope-from dougb@FreeBSD.org) Received: from mail2.fluidhosting.com (mx21.fluidhosting.com [204.14.89.4]) by mx1.freebsd.org (Postfix) with SMTP id B212A13C461 for ; Mon, 26 Nov 2007 01:15:13 +0000 (UTC) (envelope-from dougb@FreeBSD.org) Received: (qmail 14552 invoked by uid 399); 26 Nov 2007 00:48:33 -0000 Received: from localhost (HELO lap.dougb.net) (dougb@dougbarton.us@127.0.0.1) by localhost with ESMTP; 26 Nov 2007 00:48:33 -0000 X-Originating-IP: 127.0.0.1 Message-ID: <474A17DE.7010804@FreeBSD.org> Date: Sun, 25 Nov 2007 16:48:30 -0800 From: Doug Barton Organization: http://www.FreeBSD.org/ User-Agent: Thunderbird 2.0.0.9 (X11/20071119) MIME-Version: 1.0 To: Roman Divacky 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> <20071125211807.GA12250@freebsd.org> In-Reply-To: <20071125211807.GA12250@freebsd.org> X-Enigmail-Version: 0.95.5 OpenPGP: id=D5B2F0FB Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: binto , freebsd-hackers@freebsd.org, Robert Watson 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 01:15:14 -0000 Roman Divacky wrote: > On Sun, Nov 25, 2007 at 02:41:35PM -0600, Stephen Montgomery-Smith wrote: >> >> 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! > > pure computation does not need kernel operations most of the time.. ie. > multi-threading kernel wont help much ;) It has an indirect benefit by (presumably) not being in contention with the userland process, and not needing slap Giant on the whole system every few milliseconds. Doug -- This .signature sanitized for your protection