PROFIL(2-SVR3)      RISC/os Reference Manual       PROFIL(2-SVR3)



NAME
     profil - execution time profile

SYNOPSIS
     void 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 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
     times(2), monitor(3).
     prof(1) in the User's Reference Manual.

DIAGNOSTICS
     Not defined.



















                        Printed 11/19/92                   Page 1