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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | SEE ALSO | COLOPHON |
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io_uring_set_iowait(3) liburing Manual io_uring_set_iowait(3)
io_uring_set_iowait - toggle of iowait usage when waiting on CQEs
#include <liburing.h>
int io_uring_set_iowait(struct io_uring *ring,
bool enable_iowait);
By default, io_uring marks a waiting task as being in iowait if
it's sleeping waiting on events and there are pending requests.
This isn't necessarily always useful, and may be confusing on non-
storage setups where iowait isn't expected. It can also cause
extra power usage by preventing the CPU from entering lower sleep
states.
The io_uring_set_iowait(3) function allows the user to toggle this
behavior. If enable_iowait is set to true, the iowait behavior is
enabled. If it is set to false, the iowait behavior is disabled.
The iowait behavior is enabled by default when a ring is created.
If the iowait is disabled, the submit functions will set
IORING_ENTER_NO_IOWAIT in the flags argument to io_uring_enter(2).
If the kernel supports this feature, it will be marked by having
the IORING_FEAT_NO_IOWAIT feature flag set.
Available since kernel 6.15.
On success, io_uring_set_iowait(3) returns 0. On failure, it
returns -EOPNOTSUPP.
io_uring_enter(2), io_uring_submit(3), io_uring_submit_and_wait(3)
This page is part of the liburing (A library for io_uring)
project. Information about the project can be found at
⟨https://github.com/axboe/liburing⟩. If you have a bug report for
this manual page, send it to io-uring@vger.kernel.org. This page
was obtained from the project's upstream Git repository
⟨https://github.com/axboe/liburing⟩ on 2025-08-11. (At that time,
the date of the most recent commit that was found in the
repository was 2025-08-02.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
liburing-2.12 July 27, 2025 io_uring_set_iowait(3)
Pages that refer to this page: io_uring_set_iowait(3)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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