From owner-freebsd-current@FreeBSD.ORG Mon May 24 11:02:19 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 9AEE516A4CE; Mon, 24 May 2004 11:02:19 -0700 (PDT) Received: from fledge.watson.org (fledge.watson.org [204.156.12.50]) by mx1.FreeBSD.org (Postfix) with ESMTP id 394FB43D53; Mon, 24 May 2004 11:02:19 -0700 (PDT) (envelope-from robert@fledge.watson.org) Received: from fledge.watson.org (localhost [127.0.0.1]) by fledge.watson.org (8.12.11/8.12.11) with ESMTP id i4OI1l1O034555; Mon, 24 May 2004 14:01:47 -0400 (EDT) (envelope-from robert@fledge.watson.org) Received: from localhost (robert@localhost)i4OI1lWt034552; Mon, 24 May 2004 14:01:47 -0400 (EDT) (envelope-from robert@fledge.watson.org) Date: Mon, 24 May 2004 14:01:47 -0400 (EDT) From: Robert Watson X-Sender: robert@fledge.watson.org To: Kevin Oberman In-Reply-To: <20040524161726.DC2305D08@ptavv.es.net> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII cc: freebsd-current@freebsd.org Subject: Re: Disk performance under CURRENT X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 24 May 2004 18:02:19 -0000 On Mon, 24 May 2004, Kevin Oberman wrote: > Sorry, but I've been off-line for a while on travel. And my wireless > card died. :-( > > In any case, by kernel is built without witness, so I get sysctl: > unknown oid 'debug.witness_watch'. The system is a UP P4-M and not > running APIC. No INVARIANTS, either. Could you investigate the following possible areas to explore? (1) Could you see if the ATA configuration differs between the two versions, especially relating to DMA mode. There are substantial ATA driver changes, so it could be different parameters are being used. (2) Could you investigate how the performance difference changes with block size? In particular, I would expect the performance difference to be most visible with small block sizes, and least visible with large block sizes. I think before you used a 256k block size, which I would classify as on the larger side, but it would be interesting to see a table like the following fleshed out: 4.x 5.x 1 byte 256 bytes 512 bytes 1k 2k 4k 8k 16k 32k 64k 128k 256k 512k 1m For each, a sustained transfer of at least 30 seconds would be good. (3) Could you run systat -vmstat, iostat, or some other variation during the benchmark and determine the levels of system, interrupt, user, and idle CPU during the benchmark. (4) I don't know much about the machine you're running on, but could you try compiling a kernel without SMP and see what difference that makes, if any? Robert N M Watson FreeBSD Core Team, TrustedBSD Projects robert@fledge.watson.org Senior Research Scientist, McAfee Research