From owner-freebsd-smp@FreeBSD.ORG Sat May 7 07:17:26 2005 Return-Path: Delivered-To: freebsd-smp@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id ADE6816A4D8; Sat, 7 May 2005 07:17:26 +0000 (GMT) Received: from critter.freebsd.dk (0x535c0e2a.sgnxx1.adsl-dhcp.tele.dk [83.92.14.42]) by mx1.FreeBSD.org (Postfix) with ESMTP id 96D2543D2F; Sat, 7 May 2005 07:17:25 +0000 (GMT) (envelope-from phk@critter.freebsd.dk) Received: from critter.freebsd.dk (localhost [127.0.0.1]) by critter.freebsd.dk (8.13.3/8.13.3) with ESMTP id j477HPlp014466; Sat, 7 May 2005 09:17:25 +0200 (CEST) (envelope-from phk@critter.freebsd.dk) To: ticso@cicely.de From: "Poul-Henning Kamp" In-Reply-To: Your message of "Sat, 07 May 2005 00:59:27 +0200." <20050506225926.GB75629@cicely12.cicely.de> Date: Sat, 07 May 2005 09:17:25 +0200 Message-ID: <14465.1115450245@critter.freebsd.dk> Sender: phk@critter.freebsd.dk cc: smp@freebsd.org cc: current@freebsd.org cc: Kris Kennaway Subject: Re: Benchmarking mpsafevfs with parallel tarball extraction X-BeenThere: freebsd-smp@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: FreeBSD SMP implementation group List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 07 May 2005 07:17:26 -0000 In message <20050506225926.GB75629@cicely12.cicely.de>, Bernd Walter writes: >On Fri, May 06, 2005 at 01:06:35PM -0700, Kris Kennaway wrote: >> On Fri, May 06, 2005 at 11:48:52AM -0700, Kris Kennaway wrote: >> > On Fri, May 06, 2005 at 11:35:29AM -0700, Kris Kennaway wrote: >> > >> > > I might be bumping into the bandwidth of md here - when I ran less >> > > rigorous tests with lower concurrency of extractions I seemed to be >> > > getting marginally better performance (about an effective concurrency >> > > of 2.2 for both 3 and 10 simultaneous extractions - so at least it >> > > doesn't seem to degrade badly). Or this might be reflecting VFS lock >> > > contention (which there is certainly a lot of, according to mutex >> > > profiling traces). >> > >> > I suspect that I am hitting the md bandwidth: >> > >> > # dd if=/dev/zero of=/dev/md0 bs=1024k count=500 >> > 500+0 records in >> > 500+0 records out >> > 524288000 bytes transferred in 9.501760 secs (55177988 bytes/sec) > >Wasn't md's blocksize = systems's pagesize, IIRC 8k on sparc. >I'm surprised that 1k even works. That's only relevant for swap backed. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.