Re: [PATCH V2 0/3] basic busy polling support for vhost_net

[Mike Rapoport <rapoport@il.ibm.com>]

Hi Jason,

> Jason Wang <jasowang <at> redhat.com> writes:
> 
> Hi all:
> 
> This series tries to add basic busy polling for vhost net. The idea is
> simple: at the end of tx/rx processing, busy polling for new tx added
> descriptor and rx receive socket for a while.

There were several conciens Michael raised on the Razya's attempt to add
polling to vhost-net ([1], [2]). Some of them seem relevant for these
patches as well:

- What happens in overcommit scenarios?
- Have you checked the effect of polling on some macro benchmarks?

> The maximum number of time (in us) could be spent on busy polling was
> specified ioctl.

Although ioctl is definitely more appropriate interface to allow user to
tune polling, it's still not clear for me how *end user* will interact with
it and how easy it would be for him/her.

[1] http://thread.gmane.org/gmane.linux.kernel/1765593
[2] http://thread.gmane.org/gmane.comp.emulators.kvm.devel/131343

--
Sincerely yours,
Mike.