From owner-freebsd-hackers@FreeBSD.ORG Sun Nov 25 21:22:49 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 EC11416A421 for ; Sun, 25 Nov 2007 21:22:49 +0000 (UTC) (envelope-from kip.macy@gmail.com) Received: from wa-out-1112.google.com (wa-out-1112.google.com [209.85.146.178]) by mx1.freebsd.org (Postfix) with ESMTP id BDE6813C458 for ; Sun, 25 Nov 2007 21:22:49 +0000 (UTC) (envelope-from kip.macy@gmail.com) Received: by wa-out-1112.google.com with SMTP id k17so591334waf for ; Sun, 25 Nov 2007 13:22:49 -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=8Kx3Z7rdNZAxAdT9lAr4x1/pAWeHd/W4/madXM06s+M=; b=t9RKz2YjVlKMDUKoXuMi0q6XO1EBwEeidNn9QWNudwXpwxIqdMs7MKELhnB5K6m4vZX6LanXiCzih/ta2+ZHjO+bqvqgwpytkvUWPgc+n7eENewUt8wHoFt5kcu1ZC+7VSC3bPBTv21V+9VGfyuW2b0DVKQA5rf2JgkfaH2ZaMM= 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=ONjZgZ5l69qDvkc6LRxx5jLwwA0ijJPfDGDxHS9+Mw9+WZlkNdtV6ntHTBWirjA7vuwvwYY90K/71V0RoYpy8+s6X/VFyycKNFxuikiE5f6BGn0LUmkTzgrEJGAaTlUwE6jb9hbnIN53+xkDReHTZgE5hjdns/XWEIreSR68dQE= Received: by 10.115.22.1 with SMTP id z1mr124804wai.1196025769225; Sun, 25 Nov 2007 13:22:49 -0800 (PST) Received: by 10.114.13.15 with HTTP; Sun, 25 Nov 2007 13:22:49 -0800 (PST) Message-ID: Date: Sun, 25 Nov 2007 13:22:49 -0800 From: "Kip Macy" To: "Stephen Montgomery-Smith" In-Reply-To: <20071125151941.I6583@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> <20071125211807.GA12250@freebsd.org> <20071125151941.I6583@cauchy.math.missouri.edu> Cc: binto , freebsd-hackers@freebsd.org, Roman Divacky , 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: Sun, 25 Nov 2007 21:22:50 -0000 > >> > >> 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 ;) > > > > Yes, I know. But something else was also done to FreeBSD, perhaps fine > tuning with the scheduler, that did bring about massive improvements. > I assume you're using ULE. Jeff has gone to great lengths to take cache affinity into account. This may be what you are benefiting from. -Kip