Re: Xen2/NetBSD 3.1 DomU running slowly

[Stephen Borrill <netbsd%precedence.co.uk@localhost>]

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
> > > XENSHM_NPAGES
> > > in sys/arch/xen/i386/xen_shm_machdep.c
> >
> > On the DOM0 presumably?
>
> Yes
>
> > 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.

--
Stephen