Merge branch 'nanosecond-2stage' of https://github.com/vincentkfu/fio into nsec

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 289c51808a142af3a18a61aa89078a3c1e372ac0..22c5a5b8e1d845b726a2e860f5446057ff19c42e 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -1401,11 +1401,18 @@ Buffers and memory
 
 .. option:: buffer_pattern=str
 
-       If set, fio will fill the I/O buffers with this pattern. If not set, the
-       contents of I/O buffers is defined by the other options related to buffer
-       contents. The setting can be any pattern of bytes, and can be prefixed with
-       0x for hex values. It may also be a string, where the string must then be
-       wrapped with ``""``, e.g.::
+       If set, fio will fill the I/O buffers with this pattern or with the contents
+       of a file. If not set, the contents of I/O buffers are defined by the other
+       options related to buffer contents. The setting can be any pattern of bytes,
+       and can be prefixed with 0x for hex values. It may also be a string, where
+       the string must then be wrapped with ``""``. Or it may also be a filename,
+       where the filename must be wrapped with ``''`` in which case the file is
+       opened and read. Note that not all the file contents will be read if that
+       would cause the buffers to overflow. So, for example::
+
+               buffer_pattern='filename'
+
+       or::
 
                buffer_pattern="abcd"
 
@@ -1419,7 +1426,7 @@ Buffers and memory
 
        Also you can combine everything together in any order::
 
-               buffer_pattern=0xdeadface"abcd"-12
+               buffer_pattern=0xdeadface"abcd"-12'filename'
 
 .. option:: dedupe_percentage=int
 
@@ -3182,7 +3189,7 @@ Split up, the format is as follows:
 
         Total IO (KiB), bandwidth (KiB/sec), IOPS, runtime (msec)
         Submission latency: min, max, mean, stdev (usec)
-        Completion latency: min, max, mean, stdev(usec)
+        Completion latency: min, max, mean, stdev (usec)
         Completion latency percentiles: 20 fields (see below)
         Total latency: min, max, mean, stdev (usec)
         Bw (KiB/s): min, max, aggregate percentage of total, mean, stdev