Update that when sqthread_poll is enabled fio will not report submission latency. Signed-off-by: Ankit Kumar <ankit.kumar@xxxxxxxxxxx> --- HOWTO.rst | 4 +++- fio.1 | 4 +++- 2 files changed, 6 insertions(+), 2 deletions(-) diff --git a/HOWTO.rst b/HOWTO.rst index e796f961..5f8a8466 100644 --- a/HOWTO.rst +++ b/HOWTO.rst @@ -2299,7 +2299,9 @@ with the caveat that when used on the command line, they must come after the kernel of available items in the SQ ring. If this option is set, the act of submitting IO will be done by a polling thread in the kernel. This frees up cycles for fio, at the cost of using more CPU in the - system. + system. As submission is just the time it takes to fill in the sqe + entries and any syscall required to wake up the idle kernel thread, + fio will not report submission latencies. .. option:: sqthread_poll_cpu=int : [io_uring] [io_uring_cmd] diff --git a/fio.1 b/fio.1 index 9e33c9e1..a156bf5d 100644 --- a/fio.1 +++ b/fio.1 @@ -2090,7 +2090,9 @@ sqthread_poll option. Normally fio will submit IO by issuing a system call to notify the kernel of available items in the SQ ring. If this option is set, the act of submitting IO will be done by a polling thread in the kernel. This frees up cycles for fio, at -the cost of using more CPU in the system. +the cost of using more CPU in the system. As submission is just the time it +takes to fill in the sqe entries and any syscall required to wake up the idle +kernel thread, fio will not report submission latencies. .TP .BI (io_uring,io_uring_cmd)sqthread_poll_cpu \fR=\fPint When `sqthread_poll` is set, this option provides a way to define which CPU -- 2.17.1
