Re: Xen2/NetBSD 3.1 DomU running slowly

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

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)


-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
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