X-Git-Url: https://git.kernel.dk/?a=blobdiff_plain;f=HOWTO;h=2cecbbba6ab00d1b8f5cf1e5ea8ef646a0dca0b7;hb=a0ae50a6c23daa132fefde214d024d1932997259;hp=aaa46f801bd22d5ba113dc8726bafaf41d13858c;hpb=73568e1b094b86adbe2e5e19fc9b8122f0d11711;p=fio.git

diff --git a/HOWTO b/HOWTO
index aaa46f80..2cecbbba 100644
--- a/HOWTO
+++ b/HOWTO
@@ -253,7 +253,20 @@ machine.
 
 This section describes in details each parameter associated with a job.
 Some parameters take an option of a given type, such as an integer or
-a string. The following types are used:
+a string. Anywhere a numeric value is required, an arithmetic expression
+may be used, provided it is surrounded by parentheses. Supported operators
+are:
+
+	addition (+)
+	subtraction (-)
+	multiplication (*)
+	division (/)
+	modulus (%)
+	exponentiation (^)
+
+For time values in expressions, units are microseconds by default. This is
+different than for time values not in expressions (not enclosed in
+parentheses). The following types are used:
 
 str	String. This is a sequence of alpha characters.
 time	Integer with possible time suffix. In seconds unless otherwise
@@ -379,7 +392,7 @@ rw=str		Type of io pattern. Accepted values are:
 		For certain types of io the result may still be skewed a bit,
 		since the speed may be different. It is possible to specify
 		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.
+		done 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. If the
 		suffix is used with a sequential IO pattern, then the value
@@ -554,7 +567,7 @@ bssplit=str	Sometimes you want even finer grained control of the
 		while having 90% 4k writes and 10% 8k writes, you would
 		specify:
 
-		bssplit=2k/50:4k/50,4k/90,8k/10
+		bssplit=2k/50:4k/50,4k/90:8k/10
 
 blocksize_unaligned
 bs_unaligned	If this option is given, any byte size value within bsrange
@@ -823,7 +836,9 @@ number_ios=int	Fio will normally perform IOs until it has exhausted the size
 		time (or hits an error condition). With this setting, the
 		range/size can be set independently of the number of IOs to
 		perform. When fio reaches this number, it will exit normally
-		and report status.
+		and report status. Note that this does not extend the amount
+		of IO that will be done, it will only stop fio if this
+		condition is met before other end-of-job criteria.
 
 fsync=int	If writing to a file, issue a sync of the dirty data
 		for every number of blocks given. For example, if you give