From owner-freebsd-stable@FreeBSD.ORG Mon Apr 12 23:22:00 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 CFAA5106566B for ; Mon, 12 Apr 2010 23:22:00 +0000 (UTC) (envelope-from maho.nakata@gmail.com) Received: from mail-gw0-f54.google.com (mail-gw0-f54.google.com [74.125.83.54]) by mx1.freebsd.org (Postfix) with ESMTP id 7DE298FC0C for ; Mon, 12 Apr 2010 23:22:00 +0000 (UTC) Received: by gwaa12 with SMTP id a12so3415689gwa.13 for ; Mon, 12 Apr 2010 16:21:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:sender:date:message-id:to:cc :subject:from:in-reply-to:references:x-mailer:mime-version :content-type:content-transfer-encoding; bh=UULD1+W6iFrdJQPbO5fktWrPxpgy+Fzbzf7AL7PLL0k=; b=LRfiA2AImCp7D9EjWTaXwPk7IDUWqSf5e0aRJVYDpP3CSbhrB8jdrKBzFRQqper+qU QWQX/cen1wun7Rs/1NqQeWEdKo0BF5EpQxUxEboW4YSlqHk94BZOKt2NQfr4e8P003cp Frd+J1C4H2w3Hmzh86CO0uKt16kPHMeWo3t8g= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:date:message-id:to:cc:subject:from:in-reply-to:references :x-mailer:mime-version:content-type:content-transfer-encoding; b=r6/j/f3QPyXXog9qZul7FKXC66syBg7ezUGHzk2khJol8u1bMdX7Eh7iDtTcxc6fqf IwPiSGXgw0gpY3FKXI9i6jCyxJ/ZePz1uv37k7hDsaMaLGVB+Pbv4DnsgN1/7qvuCjH1 KOsGw6SxduEwcYrynjwXLKB3qsSv4d6LITqHk= Received: by 10.150.172.1 with SMTP id u1mr4213035ybe.240.1271114519506; Mon, 12 Apr 2010 16:21:59 -0700 (PDT) Received: from localhost (rikad42.riken.jp [134.160.214.42]) by mx.google.com with ESMTPS id 21sm1209080yxe.39.2010.04.12.16.21.55 (version=SSLv3 cipher=RC4-MD5); Mon, 12 Apr 2010 16:21:57 -0700 (PDT) Sender: Maho NAKATA Date: Tue, 13 Apr 2010 08:21:53 +0900 (JST) Message-Id: <20100413.082153.866357745773635148.chat95@mac.com> To: bms@incunabulum.net From: Maho NAKATA In-Reply-To: <4BC2EC9A.2020207@incunabulum.net> References: <20100412.131213.4959786962516027.chat95@mac.com> <4BC2EC9A.2020207@incunabulum.net> X-Mailer: Mew version 6.3 on Emacs 23.1 / Mule 6.0 (HANACHIRUSATO) Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit 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 23:22:01 -0000 Hi Bruce, From: Bruce Simpson Subject: Re: Only 70% of theoretical peak performance on FreeBSD 8/amd64, Corei7 920 Date: Mon, 12 Apr 2010 10:49:14 +0100 > So, where's the profiling to discover why this is the case? Ok I'll provide better documentation so that everyone can test it very clearly. (may take some time...) > Also I'm not clear on what constitutes 'theoretical peak performance' > here or how it is being calculated. So figures like these come across > as unscientific. Core i7 920 (2.66GHz) constitutes four cores. each core has four floating point operators. thus; 2.66GHz x 4 x 4 = 42.56Gflops cf. http://www.intel.com/support/processors/sb/cs-023143.htm > I'm sure this is something which can be resolved if someone sits down, > profiles the app, and makes the necessary adjustments > (e.g. pthread_setaffinity_np()) to configure CPU affinity, if the lack > of it is pessimizing your friend's app. might be. we run on the same machine. > The PMC framework is rapidly maturing, and you can use KCacheGrind > with it to visualize context switch overhead. > > But I think it's expecting a bit much to post informal results to > -stable, in an expectation of something other thaninformal suggestions > of what may help someone's maths-intensive application. BLAS is a basic linear algebra package which is used many applications. It is also used for top500 http://www.top500.org/ cf. http://www.top500.org/project/introduction via LINPACK. dgemm is LEVEL 3 BLAS, which is a very good for common PCs as calculation is CPU intensive. > If there are performance issues, then reproducible results are needed, > as well as some basic profiling effort of the system elements > involved, before people could say anything either way, or offer > further help. again, I'll provide better documentation so that everyone can test it very clearly. (may take some time...) thanks, -- Nakata Maho http://accc.riken.jp/maho/ , http://ja.openoffice.org/ Nakata Maho's PGP public keys: http://accc.riken.jp/maho/maho.pgp.txt