doc: update about size

In few cases with fio option size the number of bytes of data transferred
is actually less than what we specified. This can happen if there are
gaps or holes while doing I/O's or if we are running a mix of sequential
and random workload.
Update the documentation for that.

Fixes: https://github.com/axboe/fio/issues/1486

Signed-off-by: Ankit Kumar <ankit.kumar@samsung.com>
Signed-off-by: Vincent Fu <vincent.fu@samsung.com>

diff --git a/HOWTO.rst b/HOWTO.rst
index 2ea8455874894a0a87a2dba82a3f531bf0115c4c..0aaf033a707d331ea44be60a17c6d6a9f301f5b9 100644 (file)
--- a/HOWTO.rst
+++ b/HOWTO.rst
@@ -1875,8 +1875,11 @@ I/O size
 .. option:: size=int
 
        The total size of file I/O for each thread of this job. Fio will run until
 .. option:: size=int
 
        The total size of file I/O for each thread of this job. Fio will run until

-       this many bytes has been transferred, unless runtime is limited by other options
-       (such as :option:`runtime`, for instance, or increased/decreased by :option:`io_size`).
+       this many bytes has been transferred, unless runtime is altered by other means
+       such as (1) :option:`runtime`, (2) :option:`io_size` (3) :option:`number_ios`,
+       (4) gaps/holes while doing I/O's such as ``rw=read:16K``, or (5) sequential
+       I/O reaching end of the file which is possible when :option:`percentage_random`
+       is less than 100.

        Fio will divide this size between the available files determined by options
        such as :option:`nrfiles`, :option:`filename`, unless :option:`filesize` is
        specified by the job. If the result of division happens to be 0, the size is
        Fio will divide this size between the available files determined by options
        such as :option:`nrfiles`, :option:`filename`, unless :option:`filesize` is
        specified by the job. If the result of division happens to be 0, the size is

diff --git a/fio.1 b/fio.1
index 746c4472827f94ebd687586333443b59ebfc715f..62af0bd2e63dde718aa08cc97b4ce5359ec0a5fc 100644 (file)
--- a/fio.1
+++ b/fio.1
@@ -1676,8 +1676,11 @@ simulate a smaller amount of memory. The amount specified is per worker.
 .TP
 .BI size \fR=\fPint[%|z]
 The total size of file I/O for each thread of this job. Fio will run until
 .TP
 .BI size \fR=\fPint[%|z]
 The total size of file I/O for each thread of this job. Fio will run until

-this many bytes has been transferred, unless runtime is limited by other options
-(such as \fBruntime\fR, for instance, or increased/decreased by \fBio_size\fR).
+this many bytes has been transferred, unless runtime is altered by other means
+such as (1) \fBruntime\fR, (2) \fBio_size\fR, (3) \fBnumber_ios\fR, (4)
+gaps/holes while doing I/O's such as `rw=read:16K', or (5) sequential I/O
+reaching end of the file which is possible when \fBpercentage_random\fR is
+less than 100.

 Fio will divide this size between the available files determined by options
 such as \fBnrfiles\fR, \fBfilename\fR, unless \fBfilesize\fR is
 specified by the job. If the result of division happens to be 0, the size is
 Fio will divide this size between the available files determined by options
 such as \fBnrfiles\fR, \fBfilename\fR, unless \fBfilesize\fR is
 specified by the job. If the result of division happens to be 0, the size is