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| author | Jens Axboe <axboe@kernel.dk> | 2022-04-26 04:49:03 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2022-04-30 17:39:54 +0300 |
| commit | e1169f06d5bbdbc2b22ae4e3083a4bf75ae5ecee (patch) | |
| tree | 97d2af2ef27fd8f46011b3330cc7d859b469f09a /include/uapi/linux/io_uring.h | |
| parent | 9f010507bbc1be19dbeedc1a254209fea44adc14 (diff) | |
| download | linux-e1169f06d5bbdbc2b22ae4e3083a4bf75ae5ecee.tar.xz | |
io_uring: use TWA_SIGNAL_NO_IPI if IORING_SETUP_COOP_TASKRUN is used
If this is set, io_uring will never use an IPI to deliver a task_work
notification. This can be used in the common case where a single task or
thread communicates with the ring, and doesn't rely on
io_uring_cqe_peek().
This provides a noticeable win in performance, both from eliminating
the IPI itself, but also from avoiding interrupting the submitting
task unnecessarily.
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/20220426014904.60384-6-axboe@kernel.dk
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/uapi/linux/io_uring.h')
| -rw-r--r-- | include/uapi/linux/io_uring.h | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/include/uapi/linux/io_uring.h b/include/uapi/linux/io_uring.h index 980d82eb196e..a84f29d657c3 100644 --- a/include/uapi/linux/io_uring.h +++ b/include/uapi/linux/io_uring.h @@ -102,6 +102,14 @@ enum { #define IORING_SETUP_ATTACH_WQ (1U << 5) /* attach to existing wq */ #define IORING_SETUP_R_DISABLED (1U << 6) /* start with ring disabled */ #define IORING_SETUP_SUBMIT_ALL (1U << 7) /* continue submit on error */ +/* + * Cooperative task running. When requests complete, they often require + * forcing the submitter to transition to the kernel to complete. If this + * flag is set, work will be done when the task transitions anyway, rather + * than force an inter-processor interrupt reschedule. This avoids interrupting + * a task running in userspace, and saves an IPI. + */ +#define IORING_SETUP_COOP_TASKRUN (1U << 8) enum { IORING_OP_NOP, |