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Re: Xen2/NetBSD 3.1 DomU running slowly

On Tue, 3 Jul 2007, Manuel Bouyer wrote:
On Tue, Jul 03, 2007 at 03:15:09PM +0100, Stephen Borrill wrote:
On Sun, 3 Jun 2007, Manuel Bouyer wrote:
On Thu, May 31, 2007 at 09:24:51AM +0100, Stephen Borrill wrote:
Every now and then I get reports of a customer's DomU running slowly and,
sure enough, when I connect it takes ages to login. However, it's running
at 100% idle and the other DomU on the same box is fine. A reboot of the
DomU fixes it. When it happened today, I saw the following on the Dom0
console (which is running quickly and responsively):

xen_shm_map: ENOMEM
xen_shm_map: ENOMEM1
xvif3.0: can't map packet page

The first two are debugging, I believe, but the third looks suspicious...

The kernels are 3.1_STABLE from 20th Nov 2006. Have there been pullups
that fix this, i.e. should I be updating? I'm not in a position to upgrade
to NetBSD 4.0/Xen3 at the moment.

You may have an usage that requires more VM space for inter-domains
communications than is currenly allocated. You can try increasing
in sys/arch/xen/i386/xen_shm_machdep.c

On the DOM0 presumably?


Would doubling it be a fair increase?

Yes, in fact it really depends on how much domUs will do a full ring of I/Os
at the same time (or how much interfaces in a single domU)

I've doubled it and also now the domU is the only one on the box. The performance problems are still happening.


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