Re: xen 4.3 test report

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Fri, May 24, 2013 at 01:46:11PM +0100, George Dunlap wrote:
> On Fri, May 24, 2013 at 11:40 AM, Vasiliy Tolstov <v.tolstov@selfip.ru> wrote:
> > Hello. I'm try 4.3.0-rc2 and have very very small speed of live
> > migration (is about 2 hours for 1Gb memory) but if i start xend and
> > doing xm migrate domain successeful migrated to destionation and this
> > takes is about 3-6 seconds (i'm use infiniband)
> >
> > Why this happening?
> 
> Hmm -- I think this has been mentioned a couple of times, but I don't
> think anyone has looked into it.  I'll see if I can track it down.

I've noticed on Xen 4.1 (and Xen 4.3) that if I use a 32-bit dom0 and
local migrated any 32/64 PV/PVHVM (so four variations) guest it is incredibly slow.

(So xm save <..> in an iSCSI disk && xm restore ...)

The 'perf report' shows that dom0 spends most of its time in xen_version
(which is the yield type call).

If the same operation is done, but dom0 is a 64-bit, it is quick.

And I think this is the issue that Ian's Jackson nighlty test-system is
running in-to - which is that the migration is sooo slow that it times out.
(This is with real-linux).

Now the oddity is that this I saw this with Xen 4.1, but Vasiliy says he didn't see
this with Xen 4.1 - so perhaps the issue I am seeing is different.

Hm, I should re-run this test once more with xen 4.3 just to confirm.

> 
> >
> > And second question - why i can't migrate from 4.1.3 (xend) to
> > 4.3.0-rc2 (xend) ?
> 
> I think migration is only supported for one major release -- does it
> work from 4.1 to 4.2, then 4.2 to 4.3?
> 
>  -George
> 
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