From: Jason Wang <jasowang@xxxxxxxxxx> Date: Fri, 14 Dec 2018 12:29:54 +0800 > > On 2018/12/14 上午4:12, Michael S. Tsirkin wrote: >> On Thu, Dec 13, 2018 at 06:10:19PM +0800, Jason Wang wrote: >>> Hi: >>> >>> 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. >>> >>> Test shows about 24% improvement on TX PPS. It should benefit other >>> cases as well. >>> >>> Please review >> I think the idea of speeding up userspace access is a good one. >> However I think that moving all checks to start is way too aggressive. > > > So did packet and AF_XDP. Anyway, sharing address space and access > them directly is the fastest way. Performance is the major > consideration for people to choose backend. Compare to userspace > implementation, vhost does not have security advantages at any > level. If vhost is still slow, people will start to develop backends > based on e.g AF_XDP. Exactly, this is precisely how this kind of problem should be solved. Michael, I strongly support the approach Jason is taking here, and I would like to ask you to seriously reconsider your objections. Thank you.
