I will try it later on. Thank you. Best, Weiwei Jia
On Thu, Dec 15, 2016 at 7:13 AM, Paolo Bonzini <pbonz...@redhat.com> wrote: > > > On 15/12/2016 09:04, Stefan Hajnoczi wrote: >>> Does this feature only work for VirtIO? Does it work for SCSI or IDE? >> This only works for virtio-blk and virtio-scsi. The virtio-scsi >> dataplane support is more recent and I don't remember if it is complete. >> I've CCed Fam and Paolo who worked on virtio-scsi dataplane. >> >> Now that you have mentioned that you aren't using virtio devices, there >> is another source of lock contention that you will encounter. I/O >> request submission takes place in the vcpu thread when ioeventfd is not >> used. Only virtio uses ioeventfd so your current QEMU configuration is >> unable to let the vcpu continue execution during I/O request submission. >> >> If you care about performance then using virtio devices is probably the >> best choice. Try comparing against virtio-scsi dataplane - you should >> see a lot less jitter. > > Yes, virtio-scsi dataplane is complete. > > Paolo >
