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.
Userspace accesses through remapping tricks and next time there's a need for a new barrier we are left to figure it out by ourselves. I don't like the idea I have to say. As a first step, why don't we switch to unsafe_put_user/unsafe_get_user etc? That would be more of an apples to apples comparison, would it not? > Test shows about 24% improvement on TX PPS. It should benefit other > cases as well. > > Please review > > Jason Wang (3): > vhost: generalize adding used elem > vhost: fine grain userspace memory accessors > vhost: access vq metadata through kernel virtual address > > drivers/vhost/vhost.c | 281 ++++++++++++++++++++++++++++++++++++++---- > drivers/vhost/vhost.h | 11 ++ > 2 files changed, 266 insertions(+), 26 deletions(-) > > -- > 2.17.1
