Merge branch 'expression-parser'

Merge in the arithmetic parser.

diff --combined HOWTO
index 693eeb11b12ac28f29804ee3776ae6570f732780,57911b431fb03fa1a069c4e7d413af052b6eb4d8..2cecbbba6ab00d1b8f5cf1e5ea8ef646a0dca0b7
--- 1/HOWTO
--- 2/HOWTO
+++ b/HOWTO
@@@ -253,7 -253,20 +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 +392,7 @@@ rw=str             Type of io pattern. Accepted va
                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 +567,7 @@@ bssplit=str        Sometimes you want even fin
                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