V10/man/man2/profil.2

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.TH PROFIL 2
.CT 2 debug_tune
.SH NAME
profil \(mi execution time profile
.SH SYNOPSIS
.nf
.B void profil(buff, bufsiz, offset, scale)
.B unsigned short *buff;
.B int bufsiz, offset;
.B unsigned scale;
.fi
.SH DESCRIPTION
.I Buff
points to an area of core whose length in bytes is given by
.IR bufsiz .
After this call, the user's program counter
is examined each clock tick;
.I offset
is subtracted from it, and the result multiplied by
.IR scale ,
divided by 65536
and then rounded up to a multiple of two.
If the resulting number (\f2n\fP) is less than
.IR bufsiz ,
then
.B buff[n/2]
is incremented.
.PP
Profiling is turned off by giving a
.I scale
of 0.
It is rendered
ineffective by giving a
.I bufsiz
of 0.
Profiling is turned off when an
.I exec
is executed, but remains on in child and parent both
after a
.IR fork .
Profiling is turned off if an update in
.I buff
would cause a memory fault.
.SH "SEE ALSO"
.IR prof (1),
.IR monitor (3)
.SH BUGS
Because of the rounding up,
single byte instructions
cannot be exactly profiled.