prf(7)                                                               prf(7)


   NAME
         prf - operating system profiler

   DESCRIPTION
         The special file /dev/prf provides access to activity information in
         the operating system.  Writing the file loads the measurement
         facility with text addresses to be monitored.  Reading the file
         returns these addresses and a set of counters indicative of activity
         between adjacent text addresses.

         The recording mechanism is driven by the system clock and samples the
         program counter at line frequency.  Samples that catch the operating
         system are matched against the stored text addresses and increment
         corresponding counters for later processing.

         The file /dev/prf is a pseudo-device with no associated hardware.

   FILES
         /dev/prf

   SEE ALSO
         profiler(1M).































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