NAME | SYNOPSIS | DESCRIPTION | OPTIONS | AUTHORS | REPORTING BUGS | COPYRIGHT | SEE ALSO | COLOPHON

BTT(1)                                                                BTT(1)

NAME         top

       btt - analyse block i/o traces produces by blktrace

SYNOPSIS         top

       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         top

       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         top

       -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 specified 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
           granularity. 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 output -- 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" - showing 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" - showing 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 seconds.)

       -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
           follows:

               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         top

       btt was written by Alan D. Brunelle.  This man page was created from
       the blktrace documentation by Bas Zoetekouw.

REPORTING BUGS         top

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

COPYRIGHT         top

       Copyright © 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 General 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 documentation 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         top

       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)

COLOPHON         top

       This page is part of the blktrace (Linux block layer I/O tracer)
       project.  Information about the project can be found at [unknown --
       if you know, please contact man-pages@man7.org] It is not known how
       to report bugs for this man page; if you know, please send a mail to
       man-pages@man7.org.  This page was obtained from the project's
       upstream Git repository 
       ⟨http://git.kernel.org/cgit/linux/kernel/git/axboe/blktrace.git/⟩ on
       2017-05-03.  If you discover any rendering problems in this HTML ver‐
       sion of the page, or you believe there is a better or more up-to-date
       source for the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original man‐
       ual page), send a mail to man-pages@man7.org

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