[libvirt] [PATCH 0/2] qemu: add debug-threads support

[Daniel P. Berrange]

On Thu, Mar 10, 2016 at 02:56:04PM +0100, Marc-André Lureau wrote:
> Hi
> 
> On Thu, Mar 10, 2016 at 2:00 PM, Jiri Denemark <jdenemar at redhat.com> wrote:
> > On Thu, Mar 10, 2016 at 13:54:57 +0100, Marc-André Lureau wrote:
> >> QEMU (somewhere around 2.0) added a new sub-option to the -name flag
> >> -name debug-threads=on
> >>
> >> This causes the naming of individual QEMU threads to be helpful; e.g.
> >>  'CPU/KVM 0' or 'migration' these show up in top once the H key is
> >>  pressed, and also show up in a core dump, making it easy to figure
> >>  out which thread is which.
> >>
> >> The following 2 patches add a capability check and a qemu-conf key to
> >> enable debug-threads.
> >
> > Is there any reason against enabling this unconditionally? It sounds
> > like a nice thing to have if possible so I'd just always enable it if
> > QEMU supports that...
> >
> 
> That would be fine for me, I just wanted to be as careful as qemu is.
> They were probably thinking some monitoring tool could be confused. I
> suppose in libvirt case, there should not be furthere such monitoring,
> and libvirt is not confused. So why not? Keep the first patch,
> simplify the second?

As far as libvirt is concerned, any monitoring tool should be using
the libvirt APIs. Any tool that is talking straight to QEMU for a
libvirt managed VM is in unsupported territory and gets to keep both
pieces if it breaks. So while I understand QEMU's caution, I don't
think it is needed in libvirt.

Regards,
Daniel
-- 
|: http://berrange.com      -o-    http://www.flickr.com/photos/dberrange/ :|
|: http://libvirt.org              -o-             http://virt-manager.org :|
|: http://autobuild.org       -o-         http://search.cpan.org/~danberr/ :|
|: http://entangle-photo.org       -o-       http://live.gnome.org/gtk-vnc :|