From owner-freebsd-current@FreeBSD.ORG Sat Nov 13 10:08:06 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 C3BAB16A4CE; Sat, 13 Nov 2004 10:08:06 +0000 (GMT) Received: from pooker.samsco.org (pooker.samsco.org [168.103.85.57]) by mx1.FreeBSD.org (Postfix) with ESMTP id 4A90343D54; Sat, 13 Nov 2004 10:08:06 +0000 (GMT) (envelope-from scottl@freebsd.org) Received: from [192.168.254.11] (junior-wifi.samsco.home [192.168.254.11]) (authenticated bits=0) by pooker.samsco.org (8.12.11/8.12.10) with ESMTP id iADA9mw6008303; Sat, 13 Nov 2004 03:09:48 -0700 (MST) (envelope-from scottl@freebsd.org) Message-ID: <4195DD31.10201@freebsd.org> Date: Sat, 13 Nov 2004 03:08:49 -0700 From: Scott Long User-Agent: Mozilla/5.0 (X11; U; FreeBSD i386; en-US; rv:1.7.2) Gecko/20040929 X-Accept-Language: en-us, en MIME-Version: 1.0 To: =?ISO-8859-1?Q?S=F8ren_Schmidt?= References: <25539.1100339599@critter.freebsd.dk> <4195DB3E.2040807@DeepCore.dk> In-Reply-To: <4195DB3E.2040807@DeepCore.dk> X-Enigmail-Version: 0.86.1.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, hits=0.0 required=3.8 tests=none autolearn=no version=2.63 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on pooker.samsco.org cc: Robert Watson cc: Zoltan Frombach cc: Poul-Henning Kamp cc: freebsd-current@freebsd.org cc: Garance A Drosihn Subject: Re: 5.3-RELEASE: WARNING - WRITE_DMA interrupt timout 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: Sat, 13 Nov 2004 10:08:06 -0000 Søren Schmidt wrote: > Poul-Henning Kamp wrote: > >> In message <4195D903.2090801@DeepCore.dk>, >> =?ISO-8859-1?Q?S=F8ren_Schmidt?= wri >> tes: >> >>> Zoltan Frombach wrote: >>> >>>> This is still an issue for me. Please read this post of mine: >>>> http://lists.freebsd.org/pipermail/freebsd-stable/2004-November/009420.html >>>> >>>> >>>> Can anyone help? I would gladely install test patches to track this >>>> problem down. My system is 5.3-R. And the WRITE_DMA warning happens >>>> at least twice a day, it is so predictable. With thanks, >>> >>> >>> Hmmm, that warning is issued from ATA when requests has been returned >>> to the systems bio_taskqueue but the system hasn't finished them >>> within the timeout. Now this is an indication of the system being >>> unresponsive already at that point, or at least that was the idea. >>> It has nothing to do with a bad drive, since the interrupt was seen >>> the drive has finished the request it was asked, its the layers above >>> ATA that doesn't respond to the request beeing returned as finished. >> >> >> It is not really the task of the ata driver to fail requests at that >> time. How long is the timeout anyway ? > > > Oh, ATA doesn't fail them, it just yells that the request hasn't been > finished yet by the upper layers, it doesn't do anything to the request. > > Timeout is 5 secs, which is a pretty long time in this context IMHO.. > > However, if it can take that long time to get data pushed up the chain, > it might also explain some of the reduced I/O performance reported ? > I'm able to get 11,000+ transactions/sec and achieve PCI line rate with the aac driver and a good version of an aac controller. aac is a block driver just like ata, the only differnece is that it uses a fast interrupt handler to acknowledge the hardware, and batch-processes the completions in a mpsafe (!Giant) taskqueue. I don't see any performance problems with this, and in fact it performs quite a bit better than Linux and even Windows. I see _no_ taskqueue stalls or other strange timing or synchronization problems. Scott