Scientific Operations



PROFIL(II)                   5/15/74                   PROFIL(II)



NAME
     profil - execution time profile

SYNOPSIS
     (profil = 44.; not in assembler)
     sys  profil; buff; bufsiz; offset; scale

     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 (60th second); off-
     set 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  frac-
     tion  with  binary  point at the left: 177777(8) gives a 1-1
     mapping of pc's to words in buff; 77777(8) maps each pair of
     instruction words together.  2(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
     also  turned  off when an exec is executed but remains on in
     child and parent both after a fork.

SEE ALSO
     monitor(III), prof(I)

DIAGNOSTICS
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