Hello, > Tejun Heo <[email protected]> wrote on 03/30/2016 08:04:19 PM: > > Hello, > > On Mon, Mar 21, 2016 at 09:58:39AM +0200, Michael Rapoport wrote: > > I did some performance evaluation of different threading models in vhost, > > and in most tests replacing vhost kthread's with workqueues degrades the > > performance. Moreover, having thread management inside the vhost provides > > There really shouldn't be any difference when using unbound > workqueues. workqueue becomes a convenience thing which manages > worker pools and there shouldn't be any difference between workqueue > workers and kthreads in terms of behavior.
I agree that there really shouldn't be any performance difference, but the tests I've run show otherwise. I have no idea why and I hadn't time yet to investigate it. > > opportunity for optimization, at least for some workloads... > > What sort of optimizations are we talking about? Well, if we take Evlis (1) as for the theoretical base, there could be benefit of doing I/O scheduling inside the vhost. [1] https://www.usenix.org/system/files/conference/atc13/atc13-harel.pdf > Thanks. > > -- > tejun -- Sincerely yours, Mike.
