On Wed, Jul 27, 2016 at 09:34:25AM +0100, Stefan Hajnoczi wrote: > On Tue, Jul 26, 2016 at 06:35:30PM +0000, Yehuda Yitschak wrote: > > Thanks a lot for the detailed answer > > > > I managed to run virtio-scsi and i am benchmarking the performance > > > > just curios, does virtio-scsi deliver about the same performance as > > vhost-scsi ? > > Both virtio-scsi and vhost-scsi support many different configurations. > If achieving the best performance is critical then you need to benchmark > them yourself. > > > i was surprised to learn that vhost-scsi isn't widely used. > > i thought vhost-scsi should be the favored solution since it should be > > faster but i guess the features you mentioned are also a significant factor. > > Since virtio-scsi is QEMU userspace code it poses a lower security risk, > is easier to update in sync with QEMU itself, and has all the QEMU block > layer features. The performance of vhost-scsi and virtio-scsi should be > about the same - they both do the same thing and there's no great > advantage to a kernel thread vs userspace thread (they use essentially > the same functionality inside the kernel). > > Stefan
That would depend on the workload. I remember seeing reports of performance differences, e.g.: http://thread.gmane.org/gmane.comp.emulators.kvm.devel/93601/focus=93777 That was 4 years ago, it would be very interesting to see where we are now. -- MST