X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;ds=sidebyside;f=HOWTO;h=cc2df9b72421486d96d47e2d72220a0a5848c55a;hb=afcf77584a39461d81ff8b5c3c86fb7583172020;hp=3b60f58e0e367d1e593de9337b78b0ffb47f5d24;hpb=833491908a1afd67d27ce79257de3a4d80143d9f;p=fio.git

diff --git a/HOWTO b/HOWTO
index 3b60f58e..cc2df9b7 100644
--- a/HOWTO
+++ b/HOWTO
@@ -319,8 +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
@@ -477,6 +481,13 @@ refill_buffers	If this option is given, fio will refill the IO buffers
 		isn't specified, naturally. If data verification is enabled,
 		refill_buffers is also automatically enabled.
 
+scramble_buffers=bool	If refill_buffers is too costly and the target is
+		using data deduplication, then setting this option will
+		slightly modify the IO buffer contents to defeat normal
+		de-dupe attempts. This is not enough to defeat more clever
+		block compression attempts, but it will stop naive dedupe of
+		blocks. Default: true.
+
 nrfiles=int	Number of files to use for this job. Defaults to 1.
 
 openfiles=int	Number of files to keep open at the same time. Defaults to
@@ -513,6 +524,16 @@ 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.
 
@@ -570,9 +591,9 @@ 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
@@ -1335,13 +1356,13 @@ 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