PROFIL(2)            INTERACTIVE UNIX System            PROFIL(2)



          NAME
               profil - execution time profile

          SYNOPSIS
               void profil (buff, bufsiz, offset, scale)
               void (* offset)();
               char *buff;
               int bufsiz, 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 examined each clock tick. Then the value of
               offset is subtracted from it, and the remainder multiplied
               by scale.  If the resulting number corresponds to an entry
               inside buff, that entry is incremented.  An entry is defined
               as a series of bytes with length sizeof(short).

               The scale is interpreted as an unsigned, fixed-point frac-
               tion with binary point at the left: 0177777 (octal) gives a
               1-1 mapping of pc's to entries in buff; 077777 (octal) maps
               each pair of instruction entries together.  02(octal) 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.  Profiling will be turned off
               if an update in buff would cause a memory fault.

          SEE ALSO
               prof(1), times(2), monitor(3C).

          DIAGNOSTICS
               Not defined.



















          Rev. C Software Development Set                            Page 1