From owner-freebsd-current Wed Jan 17 11:12:53 2001 Delivered-To: freebsd-current@freebsd.org Received: from magnesium.net (toxic.magnesium.net [207.154.84.15]) by hub.freebsd.org (Postfix) with SMTP id 467C437B69E for ; Wed, 17 Jan 2001 11:12:34 -0800 (PST) Received: (qmail 21780 invoked by uid 1142); 17 Jan 2001 19:12:33 -0000 Date: 17 Jan 2001 11:12:33 -0800 Date: Wed, 17 Jan 2001 11:12:21 -0800 From: Jason Evans To: Soren Schmidt Cc: current@FreeBSD.ORG Subject: Debugging SMP instability (was Re: HEADS-UP: await/asleep removal imminent) Message-ID: <20010117111221.T61852@canonware.com> References: <20010117101342.R7240@fw.wintelcom.net> <200101171842.TAA12276@freebsd.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <200101171842.TAA12276@freebsd.dk>; from sos@freebsd.dk on Wed, Jan 17, 2001 at 07:42:26PM +0100 Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Wed, Jan 17, 2001 at 07:42:26PM +0100, Soren Schmidt wrote: > > Basically if you're expecting me or the SMP team to figure out > > what's going on without more info, you're pretty much out of luck. > > See above, not really possible, we have been trying to find some > (affordable) HW that could be used to preserve a log over a boot, > but so far I havn't been able to find anything that works, and > is fast enough to not effect the system too much... I did some research on this and am convinced that at least some video cards would work as memory buffers for KTR logs. Specifically, someone mentioned to me yesterday that their Matrox Millennium II flashes the X desktop during startup from a previous invocation across warm boots. (I pursued some alternatives and found the PCI RAM cards to be prohibitively expensive (more than $700), and sound cards to not have enough RAM except on old SoundBlaster AWE cards.) For someone with device driver experience, I expect it would be a few hours of effort to make it possible to use a second video card (or even the primary one for that matter) as a DMA region in which KTR logs can be saved, so that there is a way to debug even these spontaneous reboots you're having. Maybe I'll eventually get to implementing this myself, but to be honest, I don't have a driving need for it right now, whereas you do. =) You're experiencing a stability problem that none of us (SMPng people) can reproduce. We'd love to fix the problem, but without more information, your reports are only slightly more useful than the typical newbie "it's broken" reports, though certainly more frustrating. Jason To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message