X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=HOWTO;h=794728f3b2cf3b3d9edc3a7493ce157c8a5901ea;hp=b1dcd296d700abbb14a2c50d7146c5668aa686ba;hb=ce4864950d2ced54e0a1ccb8ef9a1e62135f1d2d;hpb=d5d94597468c6fc9821149b113f03839d7c948c8

diff --git a/HOWTO b/HOWTO
index b1dcd296..794728f3 100644
--- a/HOWTO
+++ b/HOWTO
@@ -568,6 +568,8 @@ ioengine=str	Defines how the job issues io to the file. The following
 
 			vsync	Basic readv(2) or writev(2) IO.
 
+			psyncv	Basic preadv(2) or pwritev(2) IO.
+
 			libaio	Linux native asynchronous io. Note that Linux
 				may only support queued behaviour with
 				non-buffered IO (set direct=1 or buffered=0).
@@ -828,11 +830,15 @@ thinktime_spin=int
 		to sleeping for the rest of the period specified by
 		thinktime.
 
-thinktime_blocks
+thinktime_blocks=int
 		Only valid if thinktime is set - control how many blocks
 		to issue, before waiting 'thinktime' usecs. If not set,
 		defaults to 1 which will make fio wait 'thinktime' usecs
-		after every block.
+		after every block. This effectively makes any queue depth
+		setting redundant, since no more than 1 IO will be queued
+		before we have to complete it and do our thinktime. In
+		other words, this setting effectively caps the queue depth
+		if the latter is larger.
 
 rate=int	Cap the bandwidth used by this job. The number is in bytes/sec,
 		the normal suffix rules apply. You can use rate=500k to limit