From owner-freebsd-stable@FreeBSD.ORG Mon Apr 12 10:00:50 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 541F4106564A for ; Mon, 12 Apr 2010 10:00:50 +0000 (UTC) (envelope-from adrian.chadd@gmail.com) Received: from mail-pz0-f201.google.com (mail-pz0-f201.google.com [209.85.222.201]) by mx1.freebsd.org (Postfix) with ESMTP id 24F5C8FC16 for ; Mon, 12 Apr 2010 10:00:49 +0000 (UTC) Received: by pzk39 with SMTP id 39so250565pzk.7 for ; Mon, 12 Apr 2010 03:00:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:sender:received:in-reply-to :references:date:x-google-sender-auth:received:message-id:subject :from:to:cc:content-type:content-transfer-encoding; bh=VhEaoM+WzPvM9RGWkaUmD+S7AzrIBVDX6AC048OrB1U=; b=NYZdMGvF4tPgQa05byQY2lXmkovBk9uYSKMebWYnnjbmx0q/BpUpotZvGf1+gHhmy/ O2XhjbhS38O0xEMk5wM990rMnvGsT6Gf2iPY1qAN5cYFzIQQEw9SvB4XRcOpHhjvLh8g p5F8RLiW+LUao20Y/UOlySzz+WMtfEBNc5e2M= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=X6IJwazXWXgdLMgvDm/WgZ67JGmVyYXt9ypDabnNmEiZFe8L4jFoH0TsQZfXJWRVSI 8r7pgvyxlq9Fjy816QhXfEYN3BYMsU+sANb+Vd+QFFo4A9vSqqbOS/VSzjxTfL3xVELD MKRr8Jz/vJVhDq8VF+1b+9pQ6DfNMtFNOdfZk= MIME-Version: 1.0 Sender: adrian.chadd@gmail.com Received: by 10.231.177.234 with HTTP; Mon, 12 Apr 2010 02:31:05 -0700 (PDT) In-Reply-To: <20100412.131213.4959786962516027.chat95@mac.com> References: <20100412.131213.4959786962516027.chat95@mac.com> Date: Mon, 12 Apr 2010 17:31:05 +0800 X-Google-Sender-Auth: 9b9d2ff4708c62f6 Received: by 10.141.108.14 with SMTP id k14mr2795286rvm.170.1271064666243; Mon, 12 Apr 2010 02:31:06 -0700 (PDT) Message-ID: From: Adrian Chadd 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 10:00:50 -0000 Of course, what would be helpful is actually figuring out what is going on rather than some conjecture. :) With what he said, tweaking memory allocation under FreeBSD and/or linux would change the performance characteristics and either validate or disprove his assumptions? Adrian On 12 April 2010 12:12, 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% > > Thanks, > -- Nakata Maho http://accc.riken.jp/maho/ , http://ja.openoffice.org/ > =A0 Nakata Maho's PGP public keys: http://accc.riken.jp/maho/maho.pgp.txt > > > > > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" >