Add support for randomness of any IO direction

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index a2de47067cdd11ba4ca541cae8e46910c083cda6..8768b99670a1a09e97b748bbfa6e4a6a0cab1a19 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -443,9 +443,11 @@ bs=int             The block size used for the io units. Defaults to 4k. Values
                can be given for both read and writes. If a single int is
                given, it will apply to both. If a second int is specified
                after a comma, it will apply to writes only. In other words,
-               the format is either bs=read_and_write or bs=read,write.
-               bs=4k,8k will thus use 4k blocks for reads, and 8k blocks
-               for writes. If you only wish to set the write size, you
+               the format is either bs=read_and_write or bs=read,write,trim.
+               bs=4k,8k will thus use 4k blocks for reads, 8k blocks for
+               writes, and 8k for trims. You can terminate the list with
+               a trailing comma. bs=4k,8k, would use the default value for
+               trims.. If you only wish to set the write size, you
                can do so by passing an empty read size - bs=,8k will set
                8k for writes and leave the read default value.
 
@@ -773,12 +775,10 @@ percentage_random=int     For a random workload, set how big a percentage should
                is fully random. It can be set from anywhere from 0 to 100.
                Setting it to 0 would make the workload fully sequential. Any
                setting in between will result in a random mix of sequential
-               and random IO, at the given percentages.
+               and random IO, at the given percentages. It is possible to
+               set different values for reads, writes, and trim. To do so,
+               simply use a comma separated list. See blocksize.
        
-percentage_sequential=int      See percentage_random. It is guaranteed that
-               they add up to 100. The later setting has priority, each
-               will adjust the other.
-
 norandommap    Normally fio will cover every block of the file when doing
                random IO. If this option is given, fio will just get a
                new random offset without looking at past io history. This