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* [PATCH v2 0/5] skip request refcounting
@ 2021-08-11 18:28 Pavel Begunkov
  2021-08-11 18:28 ` [PATCH v2 1/5] io_uring: move req_ref_get() and friends Pavel Begunkov
                   ` (5 more replies)
  0 siblings, 6 replies; 7+ messages in thread
From: Pavel Begunkov @ 2021-08-11 18:28 UTC (permalink / raw)
  To: Jens Axboe, io-uring

With some tricks, we can avoid refcounting in most of the cases and
so save on atomics. 1-2 are simple preparations and 3-4 are the meat.
5/5 is a hint to the compiler, which stopped to similarly optimise it
as is.

Jens tried out a prototype before, apparently it gave ~3% win for
the default read test. Not much has changed since then, so I'd
expect same result, and also hope that it should be of even greater
benefit to multithreaded workloads.

The previous version had a flaw, so it was decided to move all
completions out of IRQ and base on that assumption. On top of
io_uring-irq branch.

v2: Rebase to IRQ branch and updated descriptions. Removed prep
    patches. The main part is split in 2: dealing with submission
    refs, and completion. Added 5/5.

Pavel Begunkov (5):
  io_uring: move req_ref_get() and friends
  io_uring: remove req_ref_sub_and_test()
  io_uring: remove submission references
  io_uring: skip request refcounting
  io_uring: optimise hot path of ltimeout prep

 fs/io_uring.c | 173 +++++++++++++++++++++++++++-----------------------
 1 file changed, 94 insertions(+), 79 deletions(-)

-- 
2.32.0


^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2021-08-12  0:35 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2021-08-11 18:28 [PATCH v2 0/5] skip request refcounting Pavel Begunkov
2021-08-11 18:28 ` [PATCH v2 1/5] io_uring: move req_ref_get() and friends Pavel Begunkov
2021-08-11 18:28 ` [PATCH v2 2/5] io_uring: remove req_ref_sub_and_test() Pavel Begunkov
2021-08-11 18:28 ` [PATCH v2 3/5] io_uring: remove submission references Pavel Begunkov
2021-08-11 18:28 ` [PATCH v2 4/5] io_uring: skip request refcounting Pavel Begunkov
2021-08-11 18:28 ` [PATCH v2 5/5] io_uring: optimise hot path of ltimeout prep Pavel Begunkov
2021-08-12  0:34 ` [PATCH v2 0/5] skip request refcounting Jens Axboe

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