PROFIL(2)               GENIX Programmer's Manual               PROFIL(2)



      NAME
           profil - execution time profile

      SYNOPSIS
           profil(buff, bufsiz, offset, scale)
           char *buff;
           int bufsiz, offset, scale;

      DESCRIPTION
           Buff points to an area of core whose length (in bytes) is  given  by
           bufsiz.   After  this call, the user's program counter (pc) is exam-
           ined each clock tick (60th second); offset is  subtracted  from  it,
           and  the  result  multiplied  by  scale.   If  the  resulting number
           corresponds to a word inside buff, that word is incremented.

           The scale is interpreted as an unsigned, fixed-point  fraction  with
           binary  point at the left: 0177777(8) gives a 1-1 mapping of pc's to
           words in  buff;  077777(8)  maps  each  pair  of  instruction  words
           together.   02(8)  maps  all instructions onto the beginning of buff
           (producing a non-interrupting core clock).

           Profiling is turned off by giving a scale of 0 or 1.  It is rendered
           ineffective  by  giving a bufsiz of 0.  Profiling is turned off when
           an exec is executed, but remains on in child and parent both after a
           fork.

      SEE ALSO
           monitor(3), prof(1)

      BUGS
           Profiling does not work for interpreters; if a signal were given  to
           a process when its cpu-time clock ticked then profiling interpreters
           would be possible.






















      Printed 11/16/83                                                        1