Re: [xen-unstable bisection] complete test-amd64-i386-rhel6hvm-intel

[Andrew Jones <drjones@redhat.com>]

----- Original Message -----
> xen.org writes ("[Xen-devel] [xen-unstable bisection] complete
> test-amd64-i386-rhel6hvm-intel"):
> > branch xen-unstable
> > xen branch xen-unstable
> > job test-amd64-i386-rhel6hvm-intel
> > test xen-install
> >
> > Tree: linux
> > git://git.eu.kernel.org/pub/scm/linux/kernel/git/jeremy/xen.git
> > Tree: qemu git://hg.uk.xensource.com/HG/qemu-xen-unstable.git
> > Tree: xen http://hg.uk.xensource.com/xen-unstable.hg
> >
> > *** Found and reproduced problem changeset ***
> >
> >   Bug is in tree: xen http://hg.uk.xensource.com/xen-unstable.hg
> >   Bug introduced: bb9b81008733
> >   Bug not present: d54cfae72cd1
> >
> >
> >   changeset: 23802:bb9b81008733
> >   user: Laszlo Ersek <lersek@redhat.com>
> >   date: Wed Aug 31 15:16:14 2011 +0100
> >
> >       x86: Increase the default NR_CPUS to 256
> >
> >       Changeset 21012:ef845a385014 bumped the default to 128 about
> >       one and a
> >       half years ago. Increase it now to 256, as systems with eg.
> >       160
> >       logical CPUs are becoming (have become) common.
> >
> >       Signed-off-by: Laszlo Ersek <lersek@redhat.com>
> 
> My bisector is pretty reliable nowadays. Looking at the revision
> graph it tested before/after/before/after/before/after, ie three times
> each on the same host.
> 
> This change looks innocuous enough TBH. Is there any way this change
> could have broken a PV-on-HVM guest ? Note that RHEL6, which is what
> this is testing, seems to generally be full of bugs.

It's seems unlikely this change could break a guest, but without any
output from you tests it's impossible to tell. The fact it failed on
the same host each of the three times is probably a clue worth looking
further at. I take it that it succeeded on other hosts?

Which RHEL6 kernel release do you test with? When you say "full of bugs",
where have the bugs been filed? Are those bugs only present with the
pv-on-hvm drivers? IMO, the HV should support the guest (especially an
HVM guest), even if it was based on something as "old" as 2.6.32. So the
bugs you're finding should likely be looked at from both the host and
the guest sides, certainly not ignored.

> 
> If the problem is indeed a bug in the current RHEL6 then I will add
> this test to the "do not care" list.
> 

This attitude won't get anybody anywhere.


> Ian.
> 
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