hpc — Apollo

7.0;hpc (histogram_pc), revision 7.0, 83/09/06
HPC (HISTOGRAM_PROGRAM_COUNTER) -- Make a histogram of the program counter.
usage:  HPC  [-LOW x] [-HIGH x] [-RATE n] pathname [args...]


FORMAT

  HPC  [options] pathname [args...]


  HPC produces a histogram of the program counter during program execution,
  thus helping you locate the most time-consuming portions of your program.

  While your program is executing, HPC samples the program counter at regular
  intervals, gathering a set of data points.  Each data point is the address
  at which the program was executing -- that is, the value of the program
  counter -- when the sample was taken.

  When execution of your program has ended, HPC displays statistics and a
  histogram (bar graph) of the program counter.  Each bar corresponds to an
  area of program memory.  The length of the bar indicates how much time the
  program spent executing in the corresponding area.

  While HPC and your program are executing, serial line 3 (SIO3) (line 2 on
  DN300 systems) is not available for output.


ARGUMENTS

  pathname
  (required)       Specify the name of the program to be evaluated.

  args
  (optional)       Specify any arguments to be passed to the program "pathname".
                   These are not processed by HPC, but passed directly to your
                   program.
                   Default if omitted: no arguments passed.


OPTIONS

  If no options are specified, a histogram is produced for the entire program,
  with 500 samples taken per second.

  -LOW x           Specify lowest address ("x") to be included in the
                   histogram. "x" must be a hexadecimal value.  If this
                   option is omitted, the histogram starts at the beginning
                   of the program.

  -HIGH x          Specify highest address ("x") to be included in the
                   histogram.  "x" must be a hexadecimal value.  If this
                   option is omitted, the histogram continues to the end
                   of the program.

                   By limiting the range of addresses in the histogram with
                   -LOW and -HIGH, you can study a specific part of your
                   program, such as an I/O routine.

  -RATE n          Specify how many times ("n") HPC samples the program
                   counter per second.  "n" must be a decimal number in
                   the range 5 to 2000.  The default is 500 samples per
                   second.  A higher rate results in a more accurate
                   histogram, but tends to slow program execution.


EXAMPLE

  For a detailed example of HPC, see the HPC command description in the
  "DOMAIN System Command Reference Manual."
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