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 <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. -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.
