On Fri, Feb 10, 2023 at 02:54:29PM -0700, Jens Axboe wrote: > On 2/10/23 8:32 AM, Ming Lei wrote: > > Hello, > > > > Add two OPs which buffer is retrieved via kernel splice for supporting > > fuse/ublk zero copy. > > > > The 1st patch enhances direct pipe & splice for moving pages in kernel, > > so that the two added OPs won't be misused, and avoid potential security > > hole. > > > > The 2nd patch allows splice_direct_to_actor() caller to ignore signal > > if the actor won't block and can be done in bound time. > > > > The 3rd patch add the two OPs. > > > > The 4th patch implements ublk's ->splice_read() for supporting > > zero copy. > > > > ublksrv(userspace): > > > > https://github.com/ming1/ubdsrv/commits/io_uring_splice_buf > > > > So far, only loop/null target implements zero copy in above branch: > > > > ublk add -t loop -f $file -z > > ublk add -t none -z > > > > Basic FS/IO function is verified, mount/kernel building & fio > > works fine, and big chunk IO(BS: 64k/512k) performance gets improved > > obviously. > > Do you have any performance numbers? Simple test on ublk-loop over image in btrfs shows the improvement is 100% ~ 200%. > Also curious on liburing regression > tests, would be nice to see as it helps with review. It isn't easy since it requires ublk device so far, it looks like read to/write from one device buffer. Thanks, Ming
