It solves much of the problem, though still have overhead on traversing a wait queue + indirect calls for checking. I've been thinking to either 1. create n wait queues and bucketing waiter. E.g. log2(min_events) bucketing would remove at least half of such calls for arbitary min_events and all if min_events is pow2. 2. or dig deeper and add custom wake_up with perhaps sorted wait_queue. As I see it, it's pretty bulky and over-engineered, but maybe somebody knows an easier way? Anyway, I don't have performance numbers for that, so don't know if this would be justified. On 14/09/2019 03:31, Jens Axboe wrote: > On 9/13/19 4:28 PM, Pavel Begunkov (Silence) wrote: >> From: Pavel Begunkov <asml.silence@xxxxxxxxx> >> >> There could be a lot of overhead within generic wait_event_*() used for >> waiting for large number of completions. The patchset removes much of >> it by using custom wait event (wait_threshold). >> >> Synthetic test showed ~40% performance boost. (see patch 2) > > Nifty, from an io_uring perspective, I like this a lot. > > The core changes needed to support it look fine as well. I'll await > Peter/Ingo's comments on it. > -- Yours sincerely, Pavel Begunkov
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