TH CPUTIME 2
SH NAME
cputime, times, cycles \- cpu time in this process and children
SH SYNOPSIS
B #include <u.h>
br
B #include <libc.h>
PP
ta \w'\fLdouble 'u
B
long    times(long t[4])
PP
B
double  cputime(void)
PP
B
void    cycles(uvlong *cyclep)
SH DESCRIPTION
If
I t
is non-null,
I times
fills it in
with the number of milliseconds spent in user code, system calls,
child processes in user code, and child processes in system calls.
I Cputime
returns the sum of those same times, converted to seconds.
I Times
returns the elapsed real time, in milliseconds, that the process has been running.
PP
These functions read
BR /dev/cputime ,
opening that file when they are first called.
PP
I Cycles
reads the processor's timestamp counter of cycles since reset,
if any, and stores it via
IR cyclep .
Currently supported architectures are
BR 386 ,
BR amd64 ,
and
BR power ;
on all others,
I cycles
will store zero.
SH SOURCE
B /sys/src/libc/9sys
br
B /sys/src/libc/*/cycles.[cs]
SH SEE ALSO
IR exec (2),
IR cons (3)
SH BUGS
Only
B 386
processors starting with the Pentium have timestamp counters;
calling
I cycles
on earlier processors may execute an illegal instruction.

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