Re: Hangs

chris
2008-12-03T01:20:12Z

Sounds like your configuration is very similar to mine.
I'm also on a vanilla kernel (2.6.27.7 in my case) with kvm-79 and
AMD processors.

You sparked my curiosity on the depmod -a issue, so I spent some time trying
it on different configurations.

I have two servers:
* 1.8GHz AMD Opteron 2210 on an HP DL385G2, AMD Opteron 2210
* 2.5GHz AMD Athlon 4850e on a "green" build w/ a Gigabyte GA-MA74Gm-S2

I can reproduce it on the Gigagbyte build with ease.

On the HP DL385G2 server, I could reproduce it on one of my guests but only
once in every four times (and with multiple guests running, not sure if that
made a difference).

Like you, I also have had the feeling that my occassional hangs were more
likely on a freshly reboot, but don't have anything real conclusive to prove it.

I'm afraid I don't have an Intel-based server around right now to see if this
is an AMD-only issue. I might be able to scrounge up an HP DL380G5
(with an Intel Core 2) but I'm not sure.

Chris

On Wed, Dec 03, 2008 at 12:01:32AM +0100, xming wrote:
> > I have a way to reproduce my instance of the problem easily now. I was trying
> > to build a new kernel on my guest, and found that depmod hangs guests every
> > time.
> > In my case, I only have an amd processor - I don't have an intel
> > host to try it on, right now, but it happens on Ubuntu 8.04
> > and Ubuntu 8.10 guests, both using kvm-79 and the version of kvm that ships
> > with ubuntu 8.10.
>
> I have AMD too, vanilla kernel 2.6.27.6 and kvm-79 (although I have
> this before 79).
> the guest is SMP (UP guests hang too but less frequent).
>
> depmod does not hang here (not reproducible). Heavy CPU + heavy IO on nfs mounts
> triggers this on my side.
>
> I have a very subjective feeling that it happens more frequently when
> the host has
> less uptime (freshly rebooted).
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