On Mon, Sep 24, 2012 at 09:46:08PM +0800, Daniel Veillard wrote: > On Mon, Sep 24, 2012 at 01:35:21PM +0100, Daniel P. Berrange wrote: > > On Mon, Sep 24, 2012 at 11:48:44AM +0400, Andrey Korolyov wrote: > > > Hi, > > > > > > There is a quite annoying thing, don`t sure if I can call it a bug. > > > > > > How to reproduce: > > > > > > - start a bunch of VMs, > > > - stop libvirt, > > > - start libvirt and immediately issue any call, say, 'virsh version', > > > - delay until call completion may be fitted nearly as quadratic > > > function from number of running VMs, qemu-kvm in my case (see link > > > below). After this delay passed, any calls executed without slowdown, > > > so problem is only a 'dead gap' after restarting service. > > > > When you restart the libvirtd service, while KVM guests are running, > > the first thing libvirtd needs todo is to connect to the QEMU monitor > > for each guest and figure out its status. This can take some time > > depending on how loaded the host is in general. It will definitely > > slow libvirt API calls which need to query individual VMs, but I'm > > rather surprised that you saw any slowdown of the 'virsh version' > > command, since that should not touch VMs at all. So I think I *would* > > class this as a bug. It could be something silly like the main I/O > > event loop having some badly written bit of non-scalable code. Please > > do file a bug about this, providing as much raw data as you have > > managed to collect. > > Hum, IIRC there was a time where libvirtd would not process any > request until those reconnections were done, did that change ? Yes, a little while back we introduced code which spawns a background thread at startup to handle re-connect of VMs, so that libvirtd is not blocked for a long time. 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 :| _______________________________________________ libvirt-users mailing list libvirt-users@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvirt-users
