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Command: profil | Section: 2 | Source: UNIX v7 | File: profil.2
PROFIL(2) System Calls Manual PROFIL(2)
NAME
profil - execution time profile
SYNOPSIS
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 buf-
siz. After this call, the user's program counter (pc) is examined each
clock tick (60th second); offset is subtracted from it, and the result
multiplied by scale. If the resulting number corresponds to a word in-
side buff, that word is incremented.
The scale is interpreted as an unsigned, fixed-point fraction with bi-
nary point at the left: 0177777(8) gives a 1-1 mapping of pc's to words
in buff; 077777(8) maps each pair of instruction words together. 02(8)
maps all instructions onto the beginning of buff (producing a non-in-
terrupting 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 may be turned off if an update in buff would cause a memory
fault.
SEE ALSO
monitor(3), prof(1)
ASSEMBLER
(profil = 44.)
sys profil; buff; bufsiz; offset; scale
PROFIL(2)