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BTT(1)											   BTT(1)

NAME
       btt - analyse block i/o traces produces by blktrace

SYNOPSIS
       btt
       [ -a		  | --seek-absolute ]
       [ -A		  | --all-data ]
       [ -B <output name> | --dump-blocknos=<output name> ]
       [ -d <seconds>	  | --range-delta=<seconds> ]
       [ -D <dev;...>	  | --devices=<dev;...> ]
       [ -e <exe,...>	  | --exes=<exe,...>  ]
       [ -h		  | --help ]
       [ -i <input name>  | --input-file=<input name> ]
       [ -I <output name> | --iostat=<output name> ]
       [ -l <output name> | --d2c-latencies=<output name> ]
       [ -L <freq>	  | --periodic-latencies=<freq> ]
       [ -m <output name> | --seeks-per-second=<output name> ]
       [ -M <dev map>	  | --dev-maps=<dev map>
       [ -o <output name> | --output-file=<output name> ]
       [ -p <output name> | --per-io-dump=<output name> ]
       [ -P <output name> | --per-io-trees=<output name> ]
       [ -q <output name> | --q2c-latencies=<output name> ]
       [ -Q <output name> | --active-queue-depth=<output name> ]
       [ -r		  | --no-remaps ]
       [ -s <output name> | --seeks=<output name> ]
       [ -S <interval>	  | --iostat-interval=<interval> ]
       [ -t <sec>	  | --time-start=<sec> ]
       [ -T <sec>	  | --time-end=<sec> ]
       [ -u <output name> | --unplug-hist=<output name> ]
       [ -v		  | --verbose ]
       [ -V		  | --version ]
       [ -X		  | --easy-parse-avgs ]
       [ -z <output name> | --q2d-latencies=<output name> ]
       [ -Z		  | --do-active ]

DESCRIPTION
       btt  is a post-processing tool for the block layer IO tracing tool called blktrace(8).  As
       noted in its documentation, blktrace is a block layer IO tracing mechanism which  provides
       detailed information about request queue operations up to user space.

       btt  will  take	in  binary  dump  data from blkparse, and analyse the events, producing a
       series of output from the analysis. It will also build .dat files containing "range  data"
       --  showing  things like Q activity (periods of time while Q events are being produced), C
       activity (likewise for command completions), and etc.

       Included with the distribution is a simple 3D plotting utility, bno_plot, which	can  plot
       the block numbers btt outputs if the -B option is specified. The display will display each
       IO generated, with the time (seconds) along the X-axis, the block number (start) along the
       Y-axis and the number of blocks transferred in the IO represented along the Z-axis.

OPTIONS
       -a
       --seek-absolute
	   When specified on the command line, this directs btt to calculate seek distances based
	   solely upon the ending block address of one IO, and the start of the next.  By default
	   btt	uses  the concept of the closeness to either the beginning or end of the previous
	   IO. See the Users Manual for more details about seek distances.

       -A
       --all-data
	   Normally btt will not print out verbose information concerning  per-process	and  per-
	   device data.  If you desire that level of detail you can specify this option.

       -B <output name>
       --dump-blocknos=<output name>
	   This  option  will output absolute block numbers to three files prefixed by the speci-
	   fied output name:

	   prefix_device_r.dat
		  All read block numbers are output, first column is time  (seconds),  second  is
		  the block number, and the third column is the ending block number.

	   prefix_device_w.dat
		  All  write  block numbers are output, first column is time (seconds), second is
		  the block number, and the third column is the ending block number.

	   prefix_device_c.dat
		  All block numbers (read and write) are output, first column is time  (seconds),
		  second is the block number, and the third column is the ending block number.

       -d <seconds>
       --range-delta=<seconds>
	   btt	outputs  a  file  containing Q and C activity, the notion of active traces simply
	   means that there are Q or C traces occurring within a certain period  of  each  other.
	   The default values is 0.1 seconds; with this option allowing one to change that granu-
	   larity. The smaller the value, the more data points provided.

       -D <dev;...>
       --devices=<dev;...>
	   Normally, btt will produce data for all devices detected in the  traces  parsed.  With
	   this option, one can reduce the analysis to one or more devices provided in the string
	   passed to this option. The device identifiers are the major and minor number  of  each
	   device,  and each device identifier is separated by a colon (:). A valid specifier for
	   devices 8,0 and 8,8 would then be: 8,0:8,8.

       -e <exe,...>
       --exes=<exe,...>
	   The -e option supplies the list of executables that will have I/Os analysed.

       -h
       --help
	   Shows a short summary of possible command line option

       -i <input name>
       --input-file <input file>
	   Specifies the input file to analyse.  This should be a trace file produced by blktrace
	   (8).

       -I <output name>
       --iostat=<output name>
	   The	-I option directs btt to output iostat-like data to the specified file.  Refer to
	   the iostat (sysstat) documentation for details on the data columns.

       -l <output name>
       --d2c-latencies=<output name>
	   The -l option allows one to output per-IO D2C  latencies  respectively.  The  supplied
	   argument provides the basis for the output name for each device.

       -L <freq>
       --periodic-latencies=<freq>
	   The	-L  option allows one to output periodic latency information for both Q2C and D2C
	   latencies. The frequency specified will regulate how often an average latency is  out-
	   put -- a floating point value expressing seconds.

       -m <output name>
       --seeks-per-second=<output name>
	   Trigger  btt  to  output seeks-per-second information. The first column will contain a
	   time value (seconds), and the second column	will indicate the  number  of  seeks  per
	   second at that point.

       -M <dev map>
       --dev-maps=<dev map>
	   The -M option takes in a file generated by the provided script (gen_disk_info.py), and
	   allows for better output of device names.

       -o <output name>
       --output-file=<output name>
	   Specifies the output file name.

       -p <output name>
       --per-io-dump=<output name>
	   The -p option will generate a file that contains a list of all IO "sequences" -  show-
	   ing the parts of each IO (Q, A, I/M, D, & C).

       -P <output name>
       --per-io-trees=<output name>
	   The	-P option will generate a file that contains a list of all IO "sequences" - show-
	   ing only the Q, D & C operation times. The D & C time values are separated from the	Q
	   time values with a vertical bar.

       -q <output name>
       --q2c-latencies=<output name>
	   The	-q  option  allows  one to output per-IO Q2C latencies respectively. The supplied
	   argument provides the basis for the output name for each device.

       -Q <output name>
       --active-queue-depth=<output name>
	   The -Q option allows one to output data files showing the time stamp and the depth  of
	   active commands (those issued but not completed).

       -r
       --no-remaps
	   Ignore remap traces; older kernels did not implement the full remap PDU.

       -s <output name>
       --seeks=<output name>
	   The	-s  option  instructs btt to output seek data, the argument provided is the basis
	   for file names output. There are two files per device, read seeks and write seeks.

       -S <interval>
       --iostat-interval=<interval>
	   The -S option specifies the interval to use between data output, it defaults  to  once
	   per second.

       -t <sec>
       --time-start=<sec>
       -T <sec>
       --time-end=<sec>
	   The	-t/-T  options allow one to set a start and/or end time for analysing - analysing
	   will only be done for traces after -t's argument and before -T's argument. (-t and  -T
	   are	optional, so if you specify just -t, analysis will occur for all traces after the
	   time specified. Similarly, if only -T is specified, analysis  stops	after  -T's  sec-
	   onds.)

       -u <output name>
       --unplug-hist=<output name>
	   This option instructs btt to generate a data file containing histogram information for
	   unplug traces on a per device basis. It shows how many times an unplug was hit with	a
	   specified  number  of  IOs released. There are 21 output values into the file, as fol-
	   lows:

	       a value of 0 represents 0..4 counts
	       a value of 1 represents 5..9 counts
	       a value of 2 represents 10..14 counts
	       etc, until
	       a value of 20 represents 100+ counts

	   The file name(s) generated use the text string passed as an argument for  the  prefix,
	   followed  by  the  device  identifier in major,minor form, with a .dat extension.  For
	   example, with -u up_hist specified on the command line: up_hist_008,032.dat.

       -V
       --version
	   Shows the version of btt.

       -v
       --verbose
	   Requests a more verbose output.

       -X
       --easy-parse-avgs
	   Provide data in an easy-to-parse form and write it to a file with .avg exentsion

       -z <output name>
       --q2d-latencies=<output name>
	   The -z option allows one to output per-IO Q2D  latencies  respectively.  The  supplied
	   argument provides the basis for the output name for each device.

       -Z
       --do-active
	   The	-Z will output files containing data which can be plotted showing per-device (and
	   total system) I/O activity.

AUTHORS
       btt was written by Alan D. Brunelle.  This man page was created from the blktrace documen-
       tation by Bas Zoetekouw.

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

COPYRIGHT
       Copyright (C) 2006 Jens Axboe, Alan D. Brunelle and Nathan Scott.
       This  is free software.	You may redistribute copies of it under the terms of the GNU Gen-
       eral Public License <http://www.gnu.org/licenses/gpl.html>.  There is NO WARRANTY, to  the
       extent permitted by law.
       This  manual  page was created for Debian by Bas Zoetekouw.  It was derived from the docu-
       mentation provided by the authors and it may be used, distributed and modified  under  the
       terms of the GNU General Public License, version 2.
       On  Debian  systems,  the  text	of  the  GNU  General  Public  License	can  be  found in
       /usr/share/common-licenses/GPL-2.

SEE ALSO
       The btt Users Guide, which can be found in /usr/share/doc/blktrace/btt.pdf
       bno_plot (1), blktrace (8), blkparse (1), verify_blkparse (1), blkrawverify (1), btt (1)

blktrace git-20070910192508		September 29, 2007				   BTT(1)
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