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PATCH Jens Axboe 1 participant 1 message Jul 27, 2019

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Jens Axboe

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The following changes since commit fc220349e45144360917db48010b503a9874930d:

Merge branch 'dev' of https://github.com/smartxworks/fio (2019-07-12 10:44:45 -0600)

are available in the Git repository at:

git://git.kernel.dk/fio.git master

for you to fetch changes up to 029b42ace698eae477c5e261d2f82b191507526b:

Document io_uring feature (2019-07-26 09:53:43 -0600)

----------------------------------------------------------------
Jens Axboe (2):
engines/libaio: remove remnants of abandoned aio features Document io_uring feature

 HOWTO            | 34 ++++++++++++++++++++++++++++++++
 engines/libaio.c | 60 +++-----------------------------------------------------
 fio.1            | 23 ++++++++++++++++++++++
 3 files changed, 60 insertions(+), 57 deletions(-)

---

Diff of recent changes:

HOWTO +34 -0
index 142b83e5..81244064 100644
@@ -1805,6 +1805,11 @@ I/O engine
 		**pvsync2**
 			Basic :manpage:`preadv2(2)` or :manpage:`pwritev2(2)` I/O.
 
+		**io_uring**
+			Fast Linux native asynchronous I/O. Supports async IO
+			for both direct and buffered IO.
+			This engine defines engine specific options.
+
 		**libaio**
 			Linux native asynchronous I/O. Note that Linux may only support
 			queued behavior with non-buffered I/O (set ``direct=1`` or
@@ -2002,6 +2007,35 @@ In addition, there are some parameters which are only valid when a specific
 with the caveat that when used on the command line, they must come after the
 :option:`ioengine` that defines them is selected.
 
+.. option:: hipri : [io_uring]
+
+	If this option is set, fio will attempt to use polled IO completions.
+	Normal IO completions generate interrupts to signal the completion of
+	IO, polled completions do not. Hence they are require active reaping
+	by the application. The benefits are more efficient IO for high IOPS
+	scenarios, and lower latencies for low queue depth IO.
+
+.. option:: fixedbufs : [io_uring]
+
+	If fio is asked to do direct IO, then Linux will map pages for each
+	IO call, and release them when IO is done. If this option is set, the
+	pages are pre-mapped before IO is started. This eliminates the need to
+	map and release for each IO. This is more efficient, and reduces the
+	IO latency as well.
+
+.. option:: sqthread_poll : [io_uring]
+
+	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.
+
+.. option:: sqthread_poll_cpu : [io_uring]
+
+	When :option:`sqthread_poll` is set, this option provides a way to
+	define which CPU should be used for the polling thread.
+
 .. option:: userspace_reap : [libaio]
 
 	Normally, with the libaio engine in use, fio will use the
engines/libaio.c +3 -57

93 lines not on this page · raw message

fio.1 +23 -0
index 156201ad..2966d9d5 100644
@@ -1762,6 +1762,29 @@ In addition, there are some parameters which are only valid when a specific
 with the caveat that when used on the command line, they must come after the
 \fBioengine\fR that defines them is selected.
 .TP
+.BI (io_uring)hipri
+If this option is set, fio will attempt to use polled IO completions. Normal IO
+completions generate interrupts to signal the completion of IO, polled
+completions do not. Hence they are require active reaping by the application.
+The benefits are more efficient IO for high IOPS scenarios, and lower latencies
+for low queue depth IO.
+.TP
+.BI (io_uring)fixedbufs
+If fio is asked to do direct IO, then Linux will map pages for each IO call, and
+release them when IO is done. If this option is set, the pages are pre-mapped
+before IO is started. This eliminates the need to map and release for each IO.
+This is more efficient, and reduces the IO latency as well.
+.TP
+.BI (io_uring)sqthread_poll
+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.
+.TP
+.BI (io_uring)sqthread_poll_cpu
+When `sqthread_poll` is set, this option provides a way to define which CPU
+should be used for the polling thread.
+.TP
 .BI (libaio)userspace_reap
 Normally, with the libaio engine in use, fio will use the
 \fBio_getevents\fR\|(3) system call to reap newly returned events. With