path: root/HOWTO
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authorJens Axboe <>2019-09-05 08:59:29 -0600
committerJens Axboe <>2019-09-05 08:59:29 -0600
commit5ffd562645eceb5af6c8d068014538320d8a93e9 (patch)
tree067de271def15fc1f65443f1298000f5816617ba /HOWTO
parent4a479420d50eada0a7b9a972c529d75e2884732d (diff)
engines/io_uring: add support for registered files
This feature is exposed as a separate option, like fixedbufs, and provides a way for fio to register a set of files with the kernel. This improves IO efficiency. It is also a requirement to be able to use sqthread_poll, as that feature requires fixed files on the kernel side. Signed-off-by: Jens Axboe <>
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@@ -2033,6 +2033,12 @@ with the caveat that when used on the command line, they must come after the
map and release for each IO. This is more efficient, and reduces the
IO latency as well.
+.. option:: registerfiles : [io_uring]
+ With this option, fio registers the set of files being used with the
+ kernel. This avoids the overhead of managing file counts in the kernel,
+ making the submission and completion part more lightweight. Required
+ for the below :option:`sqthread_poll` option.
.. option:: sqthread_poll : [io_uring]
Normally fio will submit IO by issuing a system call to notify the