Date: Wed, 17 Jan 2001 20:35:24 +0100 (CET) From: Soren Schmidt <sos@freebsd.dk> To: jasone@canonware.com (Jason Evans) Cc: current@FreeBSD.ORG Subject: Re: Debugging SMP instability (was Re: HEADS-UP: await/asleep removal imminent) Message-ID: <200101171935.UAA25627@freebsd.dk> In-Reply-To: <20010117111221.T61852@canonware.com> from Jason Evans at "Jan 17, 2001 11:12:21 am"
next in thread | previous in thread | raw e-mail | index | archive | help
It seems Jason Evans wrote: > 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.) Hmm, I've been toying with this, but the el cheapo videocards I have all lose random amounts of their video RAM over a reset, probably due to the DRAM refresh being absent for too long... > 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. =) Do you need DMA ?? a simple ptr to the mem should do (and much easier to get to work)... > 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. Well, I'm not alone thats for sure, and since this has been so for months I've almost gotten to the impression that something fundamental must be wrong, however until now I've just been told to go away :) I know these problems are a bitch to find, but we need to take this at least semi professionalistic and find out whats wrong, or 5.0 will be a disater when it hits the streets. I dont have the time to play around with SMP for the time being, but I do expect the SMPng group to take these problems seriously instead of the "it works here" attitude thats been hollering down the halls lately.. Again I'll offer to run any and all code or patches to -current you guys can come up with, but I simply dont have the time to sit down and analyze into details what you have been doing... -Søren To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200101171935.UAA25627>