From owner-freebsd-bugs@FreeBSD.ORG Mon Jul 9 12:40:05 2007 Return-Path: X-Original-To: freebsd-bugs@hub.freebsd.org Delivered-To: freebsd-bugs@hub.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 69D5016A468 for ; Mon, 9 Jul 2007 12:40:05 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (freefall.freebsd.org [69.147.83.40]) by mx1.freebsd.org (Postfix) with ESMTP id 3209813C4B7 for ; Mon, 9 Jul 2007 12:40:05 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (gnats@localhost [127.0.0.1]) by freefall.freebsd.org (8.13.4/8.13.4) with ESMTP id l69Ce4jH057559 for ; Mon, 9 Jul 2007 12:40:04 GMT (envelope-from gnats@freefall.freebsd.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.13.4/8.13.4/Submit) id l69Ce4RN057558; Mon, 9 Jul 2007 12:40:04 GMT (envelope-from gnats) Resent-Date: Mon, 9 Jul 2007 12:40:04 GMT Resent-Message-Id: <200707091240.l69Ce4RN057558@freefall.freebsd.org> Resent-From: FreeBSD-gnats-submit@FreeBSD.org (GNATS Filer) Resent-To: freebsd-bugs@FreeBSD.org Resent-Reply-To: FreeBSD-gnats-submit@FreeBSD.org, Thomas Hurst Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 6289416A421 for ; Mon, 9 Jul 2007 12:39:03 +0000 (UTC) (envelope-from freaky@voi.aagh.net) Received: from spork.qfe3.net (spork.qfe3.net [212.13.207.101]) by mx1.freebsd.org (Postfix) with ESMTP id 2D23613C455 for ; Mon, 9 Jul 2007 12:39:03 +0000 (UTC) (envelope-from freaky@voi.aagh.net) Received: from [81.104.144.87] (helo=voi.aagh.net) by spork.qfe3.net with esmtp (Exim 4.66 (FreeBSD)) (envelope-from ) id 1I7s9E-000Imz-FF for FreeBSD-gnats-submit@freebsd.org; Mon, 09 Jul 2007 13:15:24 +0100 Received: from freaky by voi.aagh.net with local (Exim 4.67 (FreeBSD)) (envelope-from ) id 1I7s9E-0009fT-7n for FreeBSD-gnats-submit@freebsd.org; Mon, 09 Jul 2007 13:15:24 +0100 Message-Id: Date: Mon, 09 Jul 2007 13:15:24 +0100 From: Thomas Hurst Sender: Thomas Hurst To: FreeBSD-gnats-submit@FreeBSD.org X-Send-Pr-Version: 3.113 Cc: Subject: kern/114438: Anomalous performance with multiple arrays and amr(4) X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: Thomas Hurst List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 09 Jul 2007 12:40:05 -0000 >Number: 114438 >Category: kern >Synopsis: Anomalous performance with multiple arrays and amr(4) >Confidential: no >Severity: non-critical >Priority: medium >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Mon Jul 09 12:40:04 GMT 2007 >Closed-Date: >Last-Modified: >Originator: Thomas Hurst >Release: FreeBSD 6.2-STABLE amd64 >Organization: >Environment: System: FreeBSD voi.nightsdawn.sf 6.2-STABLE FreeBSD 6.2-STABLE #0: Wed Jul 4 13:46:52 BST 2007 root@voi.nightsdawn.sf:/usr/obj/usr/src/sys/VOI amd64 8GB dual dual core Opteron amr0: Firmware 814B, BIOS H431, 128MB RAM amrd0: 190713MB (390580224 sectors) RAID 1 (optimal) amrd1: 381485MB (781281280 sectors) RAID 1 (optimal) amrd2: 381485MB (781281280 sectors) RAID 1 (optimal) >Description: Performing heavy random IO on any one array causes other arrays to stall intermitently. For example: find /usr >/dev/null & # on amrd0 dd if=/dev/amrd1 of=/dev/null bs=128k gstat shows amrd0 doing a few hundred ops/sec and up to a few MB/s amrd1 runs at the expected 65MB/s for ~10 seconds, then stops for 2-3, before returning to 65MB/s. This behavior is seen with lighter serial transfers; I normally notice it while streaming movies or music at 100-1000k/s and daily run kicks in, causing annoying pauses in playback without the use of fairly large buffers. Multiple serial transfers on different arrays do not have the same problem; I can dd from or to all arrays without unexplained pauses. ata(4) disks on the system are unaffected. >How-To-Repeat: See above. >Fix: >Release-Note: >Audit-Trail: >Unformatted: