.TH BLKIOMON 8 "July 17, 2008" "" ""


.SH NAME
blkiomon \- monitor block device I/O based o blktrace data


.SH SYNOPSIS
.B blkiomon \-I \fIinterval\fR [ \-h \fIfile\fR ] [ \-b \fIfile\fR ]
[ \-d \fIfile\fR ] [ \-D \fIfile\fR ] [ \-Q \fIpath_name\fR
\-q \fImsg_queue_id\fR \-m \fImsg_id\fR ] [ \-V ]
.br


.SH DESCRIPTION
blkiomon is a block device I/O monitor. It periodically generates per-device
request size and request latency statistics from blktrace data. It provides
histograms as well as data that can be used to calculate min, max, average
and variance. For this purpose, it consumes D and C traces read from stdin.
Note, that this doesn't work for logical volumes, as high-level drivers
don't see the completion of the events (C).

There are options for binary output and human-readable output to files and
stdout. Output to a message queue is supported as well.

There is no need to use blkparse with blkiomon. blkiomon is capable of
consuming binary output written to stdout by blktrace.


.SH OPTIONS

\-I \fIinterval\fR
.br
\-\-interval=\fIinterval\fR
.RS
Set sample interval
.RE

\-h \fIfile\fR
.br
\-\-human\-readable=\fIfile\fR
.RS
Human-readable output file. Use '\-' for stdout.
.RE

\-b \fIfile\fR
.br
\-\-binary=\fIfile\fR
.RS
Binary output file. Use '\-' for stdout.
.RE

\-d \fIfile\fR
.br
\-\-dump-lldd=\fIfile\fR
.RS
Output file for data emitted by low level device driver.
.RE

\-D \fIfile\fR
.br
\-\-debug=\fIfile\fR
.RS
Output file for debugging data. Use '\-' for stdout.
.RE

\-Q \fIpath_name\fR
.br
\-\-msg\-queue=\fIpath_name\fR
.RS
Sets \fIpath_name\fR as path name for existing message queue to be used
for binary output.
.RE

\-q \fImsg_queue_id\fR
.br
\-\-msg\-queue\-id=\fImsg_queue_id\fR
.RS
Sets \fImsg_queue_id\fR as ID for an existing message queue to be used
for binary output.
.RE

\-m \fImsg_id\fR
.br
\-\-msg\-id=\fImsg_id\fR
.RS
Sets \fImsg_id\fR as message identifier to be used for binary output
messages written to an existing message queue.
.RE

\-V
.br
\-\-version
.RS
Print program version.
.RE


.SH EXAMPLES
To get I/O statistics for /dev/sdw every 10 seconds for a period of one hour,
use the following command:

    % blktrace /dev/sdw \-a issue \-a complete \-w 3600 \-o \- | blkiomon \-I 10 \-h \-


.SH AUTHORS
blkiomon and this man page were written by Martin Peschke.


.SH "REPORTING BUGS"
Report bugs to <linux\-btrace@vger.kernel.org>


.SH COPYRIGHT
Copyright \(co 2008 IBM Corp.
.br
This is free software.  You may redistribute copies of it under the terms of
the GNU General Public License <http://www.gnu.org/licenses/gpl.html>.
There is NO WARRANTY, to the extent permitted by law.


.SH "SEE ALSO"
btrace (8), blktrace (8), blkparse (1), verify_blkparse (1), blkrawverify (1),
btt (1)