From owner-freebsd-stable@FreeBSD.ORG Mon Apr 12 04:47:47 2010 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C78351065670 for ; Mon, 12 Apr 2010 04:47:47 +0000 (UTC) (envelope-from yanefbsd@gmail.com) Received: from qw-out-2122.google.com (qw-out-2122.google.com [74.125.92.27]) by mx1.freebsd.org (Postfix) with ESMTP id 805568FC16 for ; Mon, 12 Apr 2010 04:47:47 +0000 (UTC) Received: by qw-out-2122.google.com with SMTP id 5so1819808qwi.7 for ; Sun, 11 Apr 2010 21:47:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:received:message-id:subject:from:to:cc:content-type :content-transfer-encoding; bh=b147qckV7xDlOU503xoQctp1oyn4iL3ylxZ57j7lLfM=; b=Vl35nobI2MYKr4miChgThupkVfM31lNO5mClr1mvdvG4T1hgrciL4+jihMLO2UjkR9 INxqZpd447Qocs9QmIMksUTfSQGk7KeRFvaERcGknujwRR/XBHc4+xPviqKTGsf5psZH E3brb5HpSnw+GrYwJxtzk71KQY1/nVbNL6e0A= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=AUlOEdZhRDkNBy7zIw5uz50sNlpIyCMUoM4qjiIs9h28lycIaqZFhFTfJFvLIIxi4r 5cwUMvp27f2X+d+ngKoXCSuTcg67FtoP9doQTUZLC1mWJG693Ipeibv+mWzacGwyMq6t xP3kyBUwwfGvZnIpnKlENC56ltiYI1oyqK1Os= MIME-Version: 1.0 Received: by 10.229.28.85 with HTTP; Sun, 11 Apr 2010 21:47:46 -0700 (PDT) In-Reply-To: <20100412.131213.4959786962516027.chat95@mac.com> References: <20100412.131213.4959786962516027.chat95@mac.com> Date: Sun, 11 Apr 2010 21:47:46 -0700 Received: by 10.229.191.18 with SMTP id dk18mr5261461qcb.9.1271047666571; Sun, 11 Apr 2010 21:47:46 -0700 (PDT) Message-ID: From: Garrett Cooper To: Maho NAKATA Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: freebsd-stable@freebsd.org Subject: Re: Only 70% of theoretical peak performance on FreeBSD 8/amd64, Corei7 920 X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 12 Apr 2010 04:47:47 -0000 On Sun, Apr 11, 2010 at 9:12 PM, Maho NAKATA wrote: > Hi FreeBSD developers, > [the original article in Japanese can be found at > http://blog.goo.ne.jp/nakatamaho/e/b5f6fbc3cc6e1ac4947463eb1ca4eb0a ] > > *Abstract* > I compared the peak performance of FreeBSD 8.0/amd64 and Ubuntu 9.10 amd6= 4 using dgemm > (a linear algebra routine, matrix-matrix multiplication). > I obtained only 70% of theoretical peak performance on FreeBSD 8/amd64 an= d > almost 95% on Ubuntu 9.10 /amd64. I'm really disappointed. > > *Introduction* > I'm a friend of Gotoh Kazushige, the principal developers of GotoBLAS. He= told me that > FreeBSD is not suitable OS for scientific computing or high performance c= omputing. He says > (in Japanese and my translation): > >> I guess FreeBSD does page coloring, but I don't think FreeBSD considers = very large cache >> size which recent CPU has. Support of a very large cache on Linux is sti= ll not very will >> sophisticated, but on *BSDs, its worst; they uses too fine memory alloca= tion method, >> so we cannot expect large continuous physical memory allocation. >> Moreover, process scheduling is not so nice as *BSD employs an algorithm= that >> changes physical CPUs in turn instead of allocating one core for such ki= nd of jobs. >> Take your own benchmark, and you'll see.. > > *Result* > Machine: Core i7 920 (42.56-44.8Gflops) / DDR3 1066 > OS: FreeBSD 8.0/amd64 and Ubuntu 9.10 > GotoBLAS2: 1.13 > > dgemm result > OS =A0 =A0 =A0: FLOPS =A0 =A0 =A0 =A0 =A0 : percent in peak > FreeBSD : 32.0 GFlops =A0 =A0 : 71% > Ubuntu =A0: 42.0-42.7GFlops : 93.8%-95.3% I'm not sure if this is the exact issue, but it might be a point of reference worth investigating: http://lists.freebsd.org/pipermail/freebsd-hackers/2010-March/031004.ht= ml Thanks, -Garrett