From owner-freebsd-hackers@FreeBSD.ORG Mon Jul 16 23:21:42 2007 Return-Path: X-Original-To: hackers@freebsd.org Delivered-To: freebsd-hackers@FreeBSD.ORG Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id C789016A401 for ; Mon, 16 Jul 2007 23:21:42 +0000 (UTC) (envelope-from mv@rulez.sk) Received: from mail.rulez.sk (DaEmoN.RuLeZ.sK [84.16.32.226]) by mx1.freebsd.org (Postfix) with ESMTP id 8AB7F13C4A3 for ; Mon, 16 Jul 2007 23:21:42 +0000 (UTC) (envelope-from mv@rulez.sk) Received: from localhost (localhost [127.0.0.1]) by mail.rulez.sk (Postfix) with ESMTP id 2350F5C37; Tue, 17 Jul 2007 01:04:22 +0200 (CEST) X-Virus-Scanned: by amavisd-new at mail.rulez.sk Received: by mail.rulez.sk (Postfix, from userid 1020) id 281755C36; Tue, 17 Jul 2007 01:04:19 +0200 (CEST) Date: Tue, 17 Jul 2007 01:04:19 +0200 From: Milos Vyletel To: youshi10@u.washington.edu Message-ID: <20070716230419.GA95219@rulez.sk> References: <20070716132326.GA28016@rulez.sk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.2i Cc: hackers@freebsd.org Subject: Re: Large amounts of memory access operations cause panic under CURRENT (was "Large gap between fwrite and write, and fread and read") X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 16 Jul 2007 23:21:42 -0000 > Go figure it'd cause panics for other people. > > I wasn't using zfs at all but it panicked anyhow once (my amd64 VM only, > not my i386 test server, surprisingly). I wish I'd gotten the panic but I > walked away to get a glass of water, and there wasn't a core dump because > the VM shut down completely instead of restarting. Heh. > > My virtual machine died around 90k on the first trial though. I'll be sure > to reduce the amount and see what happens, and I'll put nanosleeps or > usleeps between the read and write ops to see if that alleviates the race > condition seen, but I'll keep the problem code around for reference later > in case I've stimulated some sort of weird bug in FreeBSD, or otherwise. > > Both my VM and test server run almost no programs though other than samba > and rsync, so you'll probably see the panic faster / more frequently than I > will if you run a lot more programs resident in memory. > > Just curious, what scheduler are you using on CURRENT, what processor do > you have, and what are your memory specs? > > Thanks, > -Garrett > Hi Garrett, this is just my desktop where is running only Xorg, fluxbox, few aterms and firefox. But i can get the panic on console too, shortly after booting. I'm using SCHED_ULE. CPU: AMD Athlon(tm) 64 X2 Dual Core Processor 4200+ (2205.01-MHz K8-class CPU) Origin = "AuthenticAMD" Id = 0x20f32 Stepping = 2 Features=0x178bfbff Features2=0x1 AMD Features=0xe2500800 AMD Features2=0x3 Cores per package: 2 usable memory = 3211718656 (3062 MB) avail memory = 3105570816 (2961 MB) For the record, it crashes few times before it hit 100k iterations, before i put debug printf in your code and increase MAX_ITERATIONS to 1m. And as far as I can tell, I had pretty much the same results as you've measured. mv