Re: problems running many guests

[Karl Rister <kmr@us.ibm.com>]

On Thursday 01 May 2008 7:16:53 pm Marcelo Tosatti wrote:
> On Thu, May 01, 2008 at 06:00:44PM -0500, Karl Rister wrote:
> > Hi
> >
> > I have been trying to do some testing of a large number of guests (72) on
> > a big multi-node IBM box (8 sockets, 32 cores, 128GB) and I am having
> > various issues with the guests.  I can get the guests to boot, but then I
> > start to have problems.  Some guests appear to stall doing I/O and some
> > become unresponsive and spin their single vcpu at 100%.
>
> Does -no-kvm-irqchip or -no-kvm-pit makes a difference? If not, please
> grab kvm_stat --once output when that happens.

I have tried -no-kvm-irqchip and it didn't help any.  I will try -no-kvm-pit 
and get the kvm_stat info for both.

>
> Also run "readprofile -r ; readprofile -m System-map-of-guest.map" with the
> host booted with "profile=kvm". Make sure all guests are running the same
> kernel image.

Will do.

>
> The profiling should be easier to understand if you have 1 guest spinning
> and remaining ones idle.



-- 
Karl Rister
IBM Linux Performance Team
kmr@us.ibm.com
(512) 838-1553 (t/l 678)

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