From owner-freebsd-hackers@FreeBSD.ORG Fri Oct 1 19:32:09 2010 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 F3F22106564A for ; Fri, 1 Oct 2010 19:32:08 +0000 (UTC) (envelope-from oppermann@networx.ch) Received: from c00l3r.networx.ch (c00l3r.networx.ch [62.48.2.2]) by mx1.freebsd.org (Postfix) with ESMTP id 681B08FC15 for ; Fri, 1 Oct 2010 19:32:07 +0000 (UTC) Received: (qmail 32509 invoked from network); 1 Oct 2010 18:57:12 -0000 Received: from localhost (HELO [127.0.0.1]) ([127.0.0.1]) (envelope-sender ) by c00l3r.networx.ch (qmail-ldap-1.03) with SMTP for ; 1 Oct 2010 18:57:12 -0000 Message-ID: <4CA630F5.9060500@networx.ch> Date: Fri, 01 Oct 2010 21:05:25 +0200 From: Andre Oppermann User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.9) Gecko/20100825 Thunderbird/3.1.3 MIME-Version: 1.0 To: freebsd-current@freebsd.org, freebsd-hackers@freebsd.org Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit X-Mailman-Approved-At: Fri, 01 Oct 2010 19:36:11 +0000 Cc: Subject: Very interesting paper: An Analysis of Linux Scalability to many Cores 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: Fri, 01 Oct 2010 19:32:09 -0000 Just saw the link to a very interesting paper on SMP scalability. A very good read and highly relevant for our efforts as well. In certain areas we may already fare better, in others we still have some work to do. An Analysis of Linux Scalability to many Cores ABSTRACT This paper analyzes the scalability of seven system applications (Exim, memcached, Apache, PostgreSQL, gmake, Psearchy, and MapReduce) running on Linux on a 48-core computer. Except for gmake, all applications trigger scalability bottlenecks inside a recent Linux kernel. Using mostly standard parallel programming techniques— this paper introduces one new technique, sloppy counters— these bottlenecks can be removed from the kernel or avoided by changing the applications slightly. Modifying the kernel required in total 3002 lines of code changes. A speculative conclusion from this analysis is that there is no scalability reason to give up on traditional operating system organizations just yet. http://pdos.csail.mit.edu/papers/linux:osdi10.pdf -- Andre