On 01/03/2020 19:23, Pavel Begunkov wrote: > On 01/03/2020 19:18, Pavel Begunkov wrote: >> There are several independent parts in the patchset, but bundled >> to make a point. >> 1-2: random stuff, that implicitly used later. >> 3-5: restore @nxt propagation >> 6-8: optimise locking in io_worker_handle_work() >> 9: optimise io_uring refcounting >> >> The next propagation bits are done similarly as it was before, but >> - nxt stealing is now at top-level, but not hidden in handlers >> - ensure there is no with REQ_F_DONT_STEAL_NEXT >> >> [6-8] is the reason to dismiss the previous @nxt propagation appoach, >> I didn't found a good way to do the same. Even though it looked >> clearer and without new flag. >> >> Performance tested it with link-of-nops + IOSQE_ASYNC: >> >> link size: 100 >> orig: 501 (ns per nop) >> 0-8: 446 >> 0-9: 416 >> >> link size: 10 >> orig: 826 >> 0-8: 776 >> 0-9: 756 > > BTW, that's basically QD1, and with contention for wqe->lock the gap should be > even wider. And another notice: "orig" actually includes [1-5], so @nxt propagation was working there. >> >> Pavel Begunkov (9): >> io_uring: clean up io_close >> io-wq: fix IO_WQ_WORK_NO_CANCEL cancellation >> io_uring: make submission ref putting consistent >> io_uring: remove @nxt from handlers >> io_uring: get next req on subm ref drop >> io-wq: shuffle io_worker_handle_work() code >> io-wq: io_worker_handle_work() optimise locking >> io-wq: optimise double lock for io_get_next_work() >> io_uring: pass submission ref to async >> >> fs/io-wq.c | 162 ++++++++++++---------- >> fs/io_uring.c | 366 ++++++++++++++++++++++---------------------------- >> 2 files changed, 258 insertions(+), 270 deletions(-) >> > -- Pavel Begunkov
