From owner-freebsd-scsi Thu Jul 24 16:59:44 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.5/8.8.5) id QAA03228 for freebsd-scsi-outgoing; Thu, 24 Jul 1997 16:59:44 -0700 (PDT) Received: from mail.cdsnet.net (mail.cdsnet.net [204.118.244.5]) by hub.freebsd.org (8.8.5/8.8.5) with ESMTP id QAA03221; Thu, 24 Jul 1997 16:59:39 -0700 (PDT) Received: from mail.cdsnet.net (mail.cdsnet.net [204.118.244.5]) by mail.cdsnet.net (8.8.6/8.8.6) with SMTP id QAA11169; Thu, 24 Jul 1997 16:59:36 -0700 (PDT) Date: Thu, 24 Jul 1997 16:59:34 -0700 (PDT) From: Jaye Mathisen To: hackers@freebsd.org, scsi@freebsd.org Subject: Ugh, DPT killing my performance... :( Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-scsi@freebsd.org X-Loop: FreeBSD.org Precedence: bulk P6-200, 64MB RAM, DPT 2 channel Ultra Wide, plugged in to Seagate Barracuda's. (4GB). DPT has 64MB RAM, version 1.10 DPT patch, 2.2.2-RELEASE disk. All disks are on the same channel (0) of the DPT. The following script renders the system essentially unusable: while (1) (cd t1 && iozone 600) (cd t2 && iozone 600) bonnie -s 200 & wait end ls -l of /root takes > 20 seconds. TOP is showing > 99% idle time. systat 2 only shows 28 interrups/sec on IRQ 15, which is the DPT controller, according to the BIOS. Transfers shows about 20-30 tps. There are these occasional burps of > 20% system time, not sure where it's going. No other processes actively running. This concerns me a bit. I tried the same thing on a 3 disk ccd array, and it runs much smoother, w/o the long delays. Of course, no parity. The DPT is configured as RAID-5, 128k stripes. Other than the grief of installing it, not sure how much benefit there would be to changing this.