X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;f=HOWTO;h=3b1eeb0606832a7808b43c309673079b3303d11f;hb=03e20d687566753b90383571e5e152c5142bdffd;hp=7cb24dd8c12e764a7ff5c5c5c813efc775418311;hpb=f42195a3ff2e186bc67968088b7cceae61ccb8f3;p=fio.git

diff --git a/HOWTO b/HOWTO
index 7cb24dd8..3b1eeb06 100644
--- a/HOWTO
+++ b/HOWTO
@@ -271,12 +271,14 @@ filename=str	Fio normally makes up a filename based on the job name,
 		can specify a number of files by separating the names with a
 		':' colon. So if you wanted a job to open /dev/sda and /dev/sdb
 		as the two working files, you would use
-		filename=/dev/sda:/dev/sdb. If the wanted filename does need to
-		include a colon, then escape that with a '\' character. For
-		instance, if the filename is "/dev/dsk/foo@3,0:c", then you would
-		use filename="/dev/dsk/foo@3,0\:c". '-' is a reserved name,
-		meaning stdin or stdout. Which of the two depends on the read/write
-		direction set.
+		filename=/dev/sda:/dev/sdb. On Windows, disk devices are accessed
+		as /dev/sda for the first device (i.e. \Device\HardDisk0\Partition0,
+		/dev/sda1 for the first partition on the first disk etc.  If the 
+		wanted filename does need to include a colon, then escape that with 
+		a '\' character. For instance, if the filename is 
+		"/dev/dsk/foo@3,0:c", then you would use filename="/dev/dsk/foo@3,0\:c". 
+		'-' is a reserved name, meaning stdin or stdout. Which of the 
+		two depends on the read/write direction set.
 
 opendir=str	Tell fio to recursively add any file it can find in this
 		directory and down the file system tree.
@@ -492,6 +494,8 @@ ioengine=str	Defines how the job issues io to the file. The following
 
 			solarisaio Solaris native asynchronous io.
 
+			windowsaio Windows native asynchronous io.
+
 			mmap	File is memory mapped and data copied
 				to/from using memcpy(3).
 
@@ -549,7 +553,14 @@ 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.