Re: [RFC PATCH V2 0/5] vhost: accelerate metadata access through vmap()

[Jason Wang]

On 2019/3/8 äå10:12, Christoph Hellwig wrote:
> On Wed, Mar 06, 2019 at 02:18:07AM -0500, Jason Wang wrote:
> > This series tries to access virtqueue metadata through kernel virtual
> > address instead of copy_user() friends since they had too much
> > overheads like checks, spec barriers or even hardware feature
> > toggling. This is done through setup kernel address through vmap() and
> > resigter MMU notifier for invalidation.
> >
> > Test shows about 24% improvement on TX PPS. TCP_STREAM doesn't see
> > obvious improvement.
> How is this going to work for CPUs with virtually tagged caches?


Anything different that you worry? I can have a test but do you know any 
archs that use virtual tag cache?

Thanks