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

From: Jason Wang
Date: Mon Mar 11 2019 - 03:13:30 EST



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