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authorPavel Begunkov <asml.silence@gmail.com>2023-01-05 11:22:28 +0000
committerJens Axboe <axboe@kernel.dk>2023-01-29 15:17:40 -0700
commit46ae7eef44f6dfd825a3bcfa43392d3ad9836ada (patch)
tree8861a0baf334affd023c35b160f33d4ccbe66ba2 /io_uring
parent326a9e482e2134d7a44b7f8f9a721b38c6bbb146 (diff)
io_uring: optimise non-timeout waiting
Unlike the jiffy scheduling version, schedule_hrtimeout() jumps a few functions before getting into schedule() even if there is no actual timeout needed. Some tests showed that it takes up to 1% of CPU cycles. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/89f880574eceee6f4899783377ead234df7b3d04.1672916894.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'io_uring')
-rw-r--r--io_uring/io_uring.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 2ec011f0ba7d..6229a49c0c33 100644
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -2479,7 +2479,9 @@ static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx,
return -EINTR;
if (unlikely(io_should_wake(iowq)))
return 0;
- if (!schedule_hrtimeout(timeout, HRTIMER_MODE_ABS))
+ if (*timeout == KTIME_MAX)
+ schedule();
+ else if (!schedule_hrtimeout(timeout, HRTIMER_MODE_ABS))
return -ETIME;
return 0;
}