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 fraction 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 is turned off if an update in buff would cause a memory fault. 

SEE ALSO

prof(1), times(2), monitor(3C). 

DIAGNOSTICS

Not defined. 

September 02, 1992