blktrace fixup + documentation
Add a little documentation on using blktrace data files.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/HOWTO b/HOWTO
index 0b43871..167ed7c 100644
--- a/HOWTO
+++ b/HOWTO
@@ -618,7 +618,12 @@
read_iolog=str Open an iolog with the specified file name and replay the
io patterns it contains. This can be used to store a
- workload and replay it sometime later.
+ workload and replay it sometime later. The iolog given
+ may also be a blktrace binary file, which allows fio
+ to replay a workload captured by blktrace. See blktrace
+ for how to capture such logging data. For blktrace replay,
+ the file needs to be turned into a blkparse binary data
+ file first (blktrace <device> -d file_for_fio.bin).
write_bw_log If given, write a bandwidth log of the jobs in this job
file. Can be used to store data of the bandwidth of the