On Thu, 07/06 13:38, Keith Busch wrote: > On Wed, Jul 05, 2017 at 09:36:31PM +0800, Fam Zheng wrote: > > This is a new protocol driver that exclusively opens a host NVMe > > controller through VFIO. It achieves better latency than linux-aio by > > completely bypassing host kernel vfs/block layer. > > > > $rw-$bs-$iodepth linux-aio nvme:// > > ---------------------------------------- > > randread-4k-1 8269 8851 > > randread-512k-1 584 610 > > randwrite-4k-1 28601 34649 > > randwrite-512k-1 1809 1975 > > > > The driver also integrates with the polling mechanism of iothread. > > > > This patch is co-authored by Paolo and me. > > > > Signed-off-by: Fam Zheng <f...@redhat.com> > > I haven't much time to do a thorough review, but in the brief time so > far the implementation looks fine to me.
Thanks for taking a look! > > I am wondering, though, if an NVMe vfio driver can be done as its own > program that qemu can link to. The SPDK driver comes to mind as such an > example, but it may create undesirable dependencies. Yes, good question. I will take a look at the current SPDK driver codebase to see if it can be linked this way. When I started this work, SPDK doesn't work with guest memory, because it requires apps to use its own hugepage powered allocators. This may have changed because I know it gained a vhost-user-scsi implementation (but that is a different story, together with vhost-user-blk). Fam
