.br
\-\-buffer\-size=\fIsize\fR
.RS
-Specifies buffer size for event extraction (scaled by 1024)
+Specifies buffer size for event extraction (scaled by 1024). The default
+buffer size is 512KiB.
.RE
\-d \fIdev\fR
.br
\-\-num\-sub=\fInum-sub\fR
.RS
-Specifies number of buffers to use
+Specifies number of buffers to use. blktrace defaults to 4 sub buffers.
.RE
\-o \fIfile\fR