On Tue, Apr 07, 2020 at 09:59:59AM +0530, gokul cg wrote: > Hi Team, > > We are observing abnormal variation in VM launch time w.r.t guest config. > > A simple VM(2gb ram no passthrough device) creation takes usually 6sec > (Time from execution of 'virsh create guest.xml to get print "Welcome to > FreeBSD"' ),but when we add a USB passthrough device launch time increased > to 18-19 sec and further increased to 39-44sec when we have increased guest > ram to 48Gb.
snip. > Note : 1) This we have seen with legacy pci passthrough device not with > vfio. And we have not noticed any perfoance impact other than qemu-init/vm > laucn time . Legacy pci passthrough support was deleted way back to 2017, and we had deprecated it for 2 years before then, in favour of VFIO. > Any suggestions to improve launch time with legacy passthrough ? Just stop using legacy PCI assignment. VFIO has been the recommended impl for 5+ years now. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
