On Mon, 2007-02-12 at 16:01 +0100, Jens Axboe wrote: > On Mon, Feb 12 2007, Rusty Russell wrote: > > Thanks Jens!! > > My pleasure, it's not often you get to make that big a performance > improvement with just a little few lines of change :-) *cough* I deliberately leave these low hanging fruit in lguest to encourage people to hack on it. Really. *cough* > I guess you'll take changes to make this driver queuing as well? It's > pretty important for good guest io performance as well. The question is whether the guest or host should queue. If you have multiple guests sharing a disk in the hose, I would think that the host is better off queuing. And this would seem to be the common case. On my todo list is: 1) Implement write barriers, (-> fsync in the host) 2) Make the host userspace program (lguest) async rather than blocking, 3) Allow multiple outstanding requests. Then it should be useful for other hypervisors. Cheers! Rusty.
