topio(1)

NAME
     topio - display and update information about the top I/O processes

SYNOPSIS
     topio [-f] [-b bytes] [-c scalls] [-s samples] [-t interval]

DESCRIPTION
     topio may be used to monitor processes making the highest use of system
     I/O resources, based on the number of I/O related system calls and number
     of bytes read or written.

     The options are as follows:

     -b  Specifies a threshold on how many bytes of I/O per second must be
         performed by a process during the sampling interval to be considered
         ``important'' enough to be reported.  bytes must be an integral value
         and a k or m suffix is allowed for scaling by 1000 and 1000000
         respectively.  The default is 100000.

     -f  Generate plain text output, suitable for writing to a file.  The
         default is to produce a window that is periodically updated using
         libcurses.

     -c  Specifies a threshold on how many read(2) or write(2) system calls
         per second must be made by a process during the sampling interval to
         be considered ``important'' enough to be reported.  scalls must be an
         integral value and a k or m suffix is allowed for scaling by 1000 and
         1000000 respectively.  The default is 50.

     -s  The argument samples defines the number of samples to be reported.
         If -s is not specified, topio will sample and report continuously.

     -t  The default update interval may be set to something other than the
         default 5 seconds.  The interval argument follows the syntax
         described in PCPIntro(1), and in the simplest form may be an unsigned
         integer (the implied units in this case are seconds).

     The output from topio is directed to standard output.

OUTPUT FORMAT
     By default (without the -f option), topio runs in full screen mode and
     the data displayed on the terminal is overwritten on each update.  This
     display consists of a heading showing some system identification
     information, the process counts by state and system-wide I/O totals,
     followed by the ``top'' I/O processes.  The reported activity appears
     under the following columns:

        _________________________________________________________________
          Column    Meaning
         ________________________________________________________________
          PID       the process ID
         ________________________________________________________________
          command   up to 7 letters of the process' argv[0]
         ________________________________________________________________
          user      up to 7 letters of the user name of the process' UID
         ________________________________________________________________
                    write(2) calls made per second during the update
                    interval
          wcall/s

         ________________________________________________________________
                    read(2) calls made per second during the update
                    interval
          rcall/s

         ________________________________________________________________
                    write throughput during the update interval
          wbyte/s
         ________________________________________________________________
                    read throughput during the update interval
          rbyte/s
         ________________________________________________________________
                    average bytes per write(2) during the update
                    interval
          wavelen

         ________________________________________________________________
                    average bytes per read(2) during the update
                    interval
          ravelen

         ________________________________________________________________
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     All numbers (system call rates, data throughput and average I/O length)
     appear as either unscaled values, or with a suffix of k or m to indicate
     scaling by 1000 or 1000000 respectively.

     topio displays the data about ``important'' processes in sorted order.
     The sort is on either (wbyte/s + rbyte/s) (the default) or on (wcall/s +
     rcall/s).  For the full screen mode of output, pressing ``s'' will toggle
     the sort keys.

     For the full screen mode of output, pressing ``q'' will terminate topio.
     Pressing any other key causes the display to be updated immediately.

EXAMPLES
     Beyond the simple use of topio to produce an interactive display
     periodically updated to show those processes exceeding the system call or
     bandwidth limits in the last 5 seconds, the following examples are
     illustrative of some other uses.

     To see what I/O the daemons are doing on a ``quiet'' system, set the
     thresholds to be very low:

          $ topio -b 1 -s 1
     To monitor high bandwidth users over time:

          $ topio -b 2m -c 100 -s 4000 -f >my.logfile


SEE ALSO
     PCPIntro(1), top(1) and pmchart(1).

AUTHORS
     The original version of topio was developed by Mark Portney and Brian
     Sumner.