Re: qemu-kvm-0.13.0 - winsows 2008 - chkdisk too slow

Daniel P. Berrange
2011-01-06T11:06:36Z

On Thu, Jan 06, 2011 at 12:19:21PM +0200, Avi Kivity wrote:
> On 01/06/2011 11:42 AM, Nikola Ciprich wrote:
> >> - run trace-cmd record -e kvm -b 100000 -P pid1 -P pid2, ctrl-C after a
> >seems like it's not possible to specify multiple pids, so
>
> Did you get 'overrun: something' reports from trace-cmd, where
> something != 0?
>
> If you're not sure, please run the trace again. Also try adding '-r
> 10' to the command line.
>
> >I've run 4 commands in parallel. Also I can't get monitor information
> >since vm is started using libvirt, so I've just used all machine's qemu-kvm
> >pids..
>
> Dan, is there a way to hijack the monitor so we can run some
> commands on it? Things like 'info registers' and disassembly.

Depends on the libvirt version. For most, you'll need to
look for the monitor path in the QEMU argv:

-chardev
+socket,id=monitor,path=/var/lib/libvirt/qemu/vmwts02.monitor,server,nowait -mon chardev=monitor,mode=readline

then, 'service libvirtd stop' and now you can connect to
the monitor at that path & run commands you want, and then
disconnect and start libvirtd again. If you run any commands
that change the VM state, things may well get confused when
you start libvirtd again, but if its just 'info registers'
etc it should be pretty safe.

If you have a new enough libvirt, then you can also send
commands directly using 'virsh qemu-monitor-command' (checking
whether you need JSON or HMP syntax first - in this case you
can see it needs HMP).

Regards,
Daniel