profil(2)                      DG/UX R4.11MU05                     profil(2)


NAME
       profil - set up execution time profiling for a process

SYNOPSIS
       #include <unistd.h>

       void  profil (buff, bufsiz, offset, scale)
       unsigned short * buff;
       unsigned int     bufsiz;
       unsigned int     offset;
       unsigned int     scale;

   where:
       buff      A pointer to the profiling buffer, an array of bytes in the
                 user's address space

       bufsiz    The number of bytes in the profiling buffer

       offset    The offset by which the profiling program counter (PC) is
                 adjusted before being multiplied by scale

       scale     A value by which the PC is multiplied before indexing into
                 the buffer array

DESCRIPTION
       After the profil call, the user's program counter (PC) is examined at
       each clock tick.  The value of offset is subtracted from the PC, and
       the result is multiplied by scale.  If the resulting number
       corresponds to an entry in buff, that entry is incremented.  An entry
       is defined as a series of bytes with length equal to sizeof(short).

       Scale is interpreted  as an unsigned, fixed-point number with the
       binary point 16 bits from the right.  For a machine whose
       instructions are 32 bits in size, 0X8000 gives a 1-1 mapping of
       instructions to entries in buff; 0x4000 maps each pair of
       instructions together, etc.

       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
       you call exec(2) but remains on in both the child and parent after a
       call to fork(2).  Profiling will be turned off if an update in buff
       would cause a memory fault.

RETURN VALUE
       None.

DIAGNOSTICS
       None.

SEE ALSO
       exec(2).


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