X-Git-Url: https://git.kernel.dk/?p=fio.git;a=blobdiff_plain;f=HOWTO;h=b67a201efd78635953b46ded0538de6110ec3e46;hp=88bd5e6c14f0f1ff356fbab964fd0a12a0a63c61;hb=723cd80afc9fdb3ca816067eb1e4790052ff6d07;hpb=d392365ee61ecf469963ca0dffe06d604332d7d2

diff --git a/HOWTO b/HOWTO
index 88bd5e6c..b67a201e 100644
--- a/HOWTO
+++ b/HOWTO
@@ -244,6 +244,7 @@ irange	Integer range with suffix. Allows value range to be given, such
 	1k:4k. If the option allows two sets of ranges, they can be
 	specified with a ',' or '/' delimiter: 1k-4k/8k-32k. Also see
 	int.
+float_list	A list of floating numbers, separated by a ':' character.
 
 With the above in mind, here follows the complete list of fio job
 parameters.
@@ -318,8 +319,12 @@ rw=str		Type of io pattern. Accepted values are:
 		a number of IO's to do before getting a new offset, this is
 		one by appending a ':<nr>' to the end of the string given.
 		For a random read, it would look like 'rw=randread:8' for
-		passing in an offset modifier with a value of 8. See the
-		'rw_sequencer' option.
+		passing in an offset modifier with a value of 8. If the
+		postfix is used with a sequential IO pattern, then the value
+		specified will be added to the generated offset for each IO.
+		For instance, using rw=write:4k will skip 4k for every
+		write. It turns sequential IO into sequential IO with holes.
+		See the 'rw_sequencer' option.
 
 rw_sequencer=str If an offset modifier is given by appending a number to
 		the rw=<str> line, then this option controls how that
@@ -512,6 +517,16 @@ ioengine=str	Defines how the job issues io to the file. The following
 			libaio	Linux native asynchronous io. Note that Linux
 				may only support queued behaviour with
 				non-buffered IO (set direct=1 or buffered=0).
+				This engine also has a sub-option,
+				userspace_reap. To set it, use
+				ioengine=libaio:userspace_reap. Normally, with
+				the libaio engine in use, fio will use the
+				io_getevents system call to reap newly returned
+				events. With this flag turned on, the AIO ring
+				will be read directly from user-space to reap
+				events. The reaping mode is only enabled when
+				polling for a minimum of 0 events (eg when
+				iodepth_batch_complete=0).
 
 			posixaio glibc posix asynchronous io.
 
@@ -569,9 +584,9 @@ ioengine=str	Defines how the job issues io to the file. The following
 				for more info on GUASI.
 
 			rdma    The RDMA I/O engine  supports  both  RDMA
-				memory semantic(RDMA_WRITE/RDMA_READ) and
-				channel semantic(Send/Recv) in InfiniBand, RoCE
-				and iWarp environment.
+				memory semantics (RDMA_WRITE/RDMA_READ) and
+				channel semantics (Send/Recv) for the
+				InfiniBand, RoCE and iWARP protocols.
 
 			external Prefix to specify loading an external
 				IO engine object file. Append the engine
@@ -678,10 +693,10 @@ norandommap	Normally fio will cover every block of the file when doing
 		blocksizes (via bsrange=) are used, since fio only tracks
 		complete rewrites of blocks.
 
-softrandommap	See norandommap. If fio runs with the random block map enabled
-		and it fails to allocate the map, if this option is set it
-		will continue without a random block map. As coverage will
-		not be as complete as with random maps, this option is
+softrandommap=bool See norandommap. If fio runs with the random block map
+		enabled and it fails to allocate the map, if this option is
+		set it will continue without a random block map. As coverage
+		will not be as complete as with random maps, this option is
 		disabled by default.
 
 nice=int	Run the job with the given nice value. See man nice(2).
@@ -1120,6 +1135,18 @@ disable_slat=bool Disable measurements of submission latency numbers. See
 disable_bw=bool	Disable measurements of throughput/bandwidth numbers. See
 		disable_lat.
 
+clat_percentiles=bool Enable the reporting of percentiles of
+		 completion latencies.
+
+percentile_list=float_list Overwrite the default list of percentiles
+		for completion latencies. Each number is a floating
+		number in the range (0,100], and the maximum length of
+		the list is 20. Use ':' to separate the numbers, and
+		list the numbers in ascending order. For example,
+		--percentile_list=99.5:99.9 will cause fio to report
+		the values of completion latency below which 99.5% and
+		99.9% of the observed latencies fell, respectively.
+
 gtod_reduce=bool Enable all of the gettimeofday() reducing options
 		(disable_clat, disable_slat, disable_bw) plus reduce
 		precision of the timeout somewhat to really shrink
@@ -1322,13 +1349,13 @@ Split up, the format is as follows:
 
 	version, jobname, groupid, error
 	READ status:
-		KB IO, bandwidth (KB/sec), runtime (msec)
+		Total IO (KB), bandwidth (KB/sec), runtime (msec)
 		Submission latency: min, max, mean, deviation
 		Completion latency: min, max, mean, deviation
 		Total latency: min, max, mean, deviation
 		Bw: min, max, aggregate percentage of total, mean, deviation
 	WRITE status:
-		KB IO, bandwidth (KB/sec), runtime (msec)
+		Total IO (KB), bandwidth (KB/sec), runtime (msec)
 		Submission latency: min, max, mean, deviation
 		Completion latency: min, max, mean, deviation
 		Total latency: min, max, mean, deviation