Subject: Re: freezes with NetBSD 3.99.3 / Xen 2.0.5
To: Malcolm Herbert <firstname.lastname@example.org>
From: Manuel Bouyer <email@example.com>
Date: 05/12/2005 20:48:28
On Thu, May 12, 2005 at 09:42:29AM +1000, Malcolm Herbert wrote:
> Not sure whether this is a Xen issue or something to do with -current,
> hence the cross posting ...
> I have put together a box running NetBSD/Xen with Xen kernel 2.0.5 and
> NetBSD 3.99.3.
> After some initial problems getting the machine to boot with grub it
> seems to be mostly fine. Unfortunately the machine appears to freeze
> completely for a few seconds every ten minutes or so. On monitoring
> the console I have noticed the external USB keyboard detach and
> reattach, although the freezes still occur with it unplugged.
> Also, it seems that the system clock is running slow - by almost 40
> minutes after three days and root in domain0 doesn't seem to be able to
> change it with date or ntpd. Thirdly, whenever there is a lot of
> serial port activity (even at 9600bd) the machine seems to slow down
> markedly - I haven't done any major testing on this, but I have noticed
> that a networked mp3 stream from the machine to my hardware mp3 player
> begins to get very very choppy at the same time ...
> Has anyone else noticed these problems with a setup like this?
Well, no. I have a Xen system with an UPS connected to the serial console.
The monitoring daemon talks to the UPS periodically and I never noticed
any slowdown. I don't use USB on this box, though.
Also, ntpd doesn't have problems on this box:
mooney:/home/hera1/permanents/bouyer>ntpq -c peer
remote refid st t when poll reach delay offset jitter
*olympe-61-0 18.104.22.168 2 u 42 64 376 0.257 3.604 0.111
+routeur-ipv6 22.214.171.124 2 u 59 64 376 0.254 2.797 0.123
what does 'systat vm' shows when this happens, especially the interrupts
states ? You'll probably want a display highter than 24 rows to have all
interrupt sources displayed.
> Also, I've configured grub to use the PC console to display the menu
> and use the serial console as the console for the domain0 NetBSD
> instance. As I use screen on the serial console I keep invoking Xen
> kernel's attention string accidentally as it uses three ^A in a row ...
> is there any way to tell Xen to use some other string, say ^T or
> something else?
Not that I know. I'd like to change it as well, as tip will trap ^A
> Or perhaps tell Xen to ignore the serial console
> altogether and just use the PC console?
If you have a serial console I strongly suggest that you keep Xen under
serial console too. sending a R to Xen is usefull on occasions :)
And before doing this, send a 'q' to get enouth debug infos if the
NetBSD domain0 is dead.
Manuel Bouyer <firstname.lastname@example.org>
NetBSD: 26 ans d'experience feront toujours la difference