From owner-freebsd-current Mon Mar 20 23:33:19 1995 Return-Path: current-owner Received: (from majordom@localhost) by freefall.cdrom.com (8.6.10/8.6.6) id XAA07020 for current-outgoing; Mon, 20 Mar 1995 23:33:19 -0800 Received: from news.iadfw.net (jbryant@news.iadfw.net [204.178.72.99]) by freefall.cdrom.com (8.6.10/8.6.6) with ESMTP id XAA07014 for ; Mon, 20 Mar 1995 23:33:18 -0800 Received: from localhost (jbryant@localhost) by news.iadfw.net (8.6.5/8.6.6) id BAA02285; Tue, 21 Mar 1995 01:32:54 -0600 From: Jim Bryant Message-Id: <199503210732.BAA02285@news.iadfw.net> Subject: Re: iozone read vs. write To: kuku@gilberto.physik.rwth-aachen.de (Christoph P. Kukulies) Date: Tue, 21 Mar 1995 01:32:52 -0600 (CST) Cc: freebsd-current@FreeBSD.org In-Reply-To: <199503201602.RAA02319@gilberto.physik.rwth-aachen.de> from "Christoph P. Kukulies" at Mar 20, 95 05:02:31 pm X-Mailer: ELM [version 2.4 PL23] Content-Type: text Content-Length: 1217 Sender: current-owner@FreeBSD.org Precedence: bulk In reply: > Date: Mon, 20 Mar 1995 17:02:31 +0100 > From: "Christoph P. Kukulies" > To: freebsd-current@freefall.cdrom.com > Subject: iozone read vs. write > > iozone 13 ... > > Writing the 13 Megabyte file, 'iozone.tmp'...15.085938 seconds > Reading the file...4.000000 seconds > > IOZONE performance measurements: > 903589 bytes/second for writing the file > 3407872 bytes/second for reading the file > > Does anone have an explanation why the number diverge to such an extent? > (System is a 32 MB 486DX2/66 EIDE 2 Quantum 540 system) caching. Try modifying the sources to change the number of iterations in auto-mode. I find on a 64 meg system that the read and write times converge to hardware speed when it hits a file size of 32 megs. The test is essentially useless until you get past the cache, that is unless you are measuring caching performance. Jim -- All opinions expressed are mine, if you | "I will not be pushed, stamped, think otherwise, then go jump into turbid | briefed, debriefed, indexed, or radioactive waters and yell WAHOO !!! | numbered!" - #1, "The Prisoner" jbryant@server.iadfw.net, System administrator, Internet America