The following changes since commit 47f6bdecbb82f00c698263e0e96b33977c1adb64:
Merge branch 'master' of ssh://brick.kernel.dk/data/git/fio (2010-11-30 20:49:24 +0100)
are available in the git repository at:
git://git.kernel.dk/fio.git master
Jens Axboe (1):
Sync HOWTO iodepth option with man page
Sebastian Kayser (1):
fio.1: Add ioengines heads up to the iodepth section
HOWTO | 9 ++++++++-
fio.1 | 8 +++++++-
2 files changed, 15 insertions(+), 2 deletions(-)
---
Diff of recent changes:
diff --git a/HOWTO b/HOWTO
index 7cb24dd..dc21afc 100644
--- a/HOWTO
+++ b/HOWTO
@@ -549,7 +549,14 @@ ioengine=str Defines how the job issues io to the file. The following
iodepth=int This defines how many io units to keep in flight against
the file. The default is 1 for each file defined in this
job, can be overridden with a larger value for higher
- concurrency.
+ concurrency. Note that increasing iodepth beyond 1 will not
+ affect synchronous ioengines (except for small degress when
+ verify_async is in use). Even async engines my impose OS
+ restrictions causing the desired depth not to be achieved.
+ This may happen on Linux when using libaio and not setting
+ direct=1, since buffered IO is not async on that OS. Keep an
+ eye on the IO depth distribution in the fio output to verify
+ that the achieved depth is as expected. Default: 1.
iodepth_batch_submit=int
iodepth_batch=int This defines how many pieces of IO to submit at once.
diff --git a/fio.1 b/fio.1
index b0276c4..eaa1c40 100644
--- a/fio.1
+++ b/fio.1
@@ -379,7 +379,13 @@ Loads an external I/O engine object file. Append the engine filename as
.RE
.TP
.BI iodepth \fR=\fPint
-Number of I/O units to keep in flight against the file. Default: 1.
+Number of I/O units to keep in flight against the file. Note that increasing
+iodepth beyond 1 will not affect synchronous ioengines (except for small
+degress when verify_async is in use). Even async engines my impose OS
+restrictions causing the desired depth not to be achieved. This may happen on
+Linux when using libaio and not setting \fBdirect\fR=1, since buffered IO is
+not async on that OS. Keep an eye on the IO depth distribution in the
+fio output to verify that the achieved depth is as expected. Default: 1.
.TP
.BI iodepth_batch \fR=\fPint
Number of I/Os to submit at once. Default: \fBiodepth\fR.
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