Use specified buffer_pattern (if given) for all io_u fills
For compression, we use a fixed '0' pattern. But if the user
specified a pattern to use in the job file, then we should
use that instead. It could slightly skew the compression ratio
for long patterns, but that is to be expected.
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/fio.1 b/fio.1
index 77faa45..c3193a2 100644
--- a/fio.1
+++ b/fio.1
@@ -476,9 +476,12 @@
.BI buffer_compress_percentage \fR=\fPint
If this is set, then fio will attempt to provide IO buffer content (on WRITEs)
that compress to the specified level. Fio does this by providing a mix of
-random data and zeroes. Note that this is per block size unit, for file/disk
-wide compression level that matches this setting, you'll also want to set
-\fBrefill_buffers\fR.
+random data and a fixed pattern. The fixed pattern is either zeroes, or the
+pattern specified by \fBbuffer_pattern\fR. If the pattern option is used, it
+might skew the compression ratio slightly. Note that this is per block size
+unit, for file/disk wide compression level that matches this setting. Note
+that this is per block size unit, for file/disk wide compression level that
+matches this setting, you'll also want to set refill_buffers.
.TP
.BI buffer_compress_chunk \fR=\fPint
See \fBbuffer_compress_percentage\fR. This setting allows fio to manage how