MICROUPTIME(9) FreeBSD Kernel Developer's Manual MICROUPTIME(9)
NAME
binuptime, getbinuptime, microuptime, getmicrouptime, nanouptime,
getnanouptime - get the time elapsed since boot
SYNOPSIS
#include <sys/time.h>
void
binuptime(struct bintime *bt);
void
getbinuptime(struct bintime *bt);
void
microuptime(struct timeval *tv);
void
getmicrouptime(struct timeval *tv);
void
nanouptime(struct timespec *ts);
void
getnanouptime(struct timespec *tsp);
DESCRIPTION
The binuptime() and getbinuptime() functions store the time elapsed since
boot as a struct bintime at the address specified by bt. The
microuptime() and getmicrouptime() functions perform the same utility,
but record the elapsed time as a struct timeval instead. Similarly the
nanouptime() and getnanouptime() functions store the elapsed time as a
struct timespec. The used structures are described in timeval(3).
The binuptime(), microuptime(), and nanouptime() functions always query
the timecounter to return the current time as precisely as possible.
Whereas getbinuptime(), getmicrouptime(), and getnanouptime() functions
are abstractions which return a less precise, but faster to obtain, time.
The intent of the getbinuptime(), getmicrouptime(), and getnanouptime()
functions is to enforce the user's preference for timer accuracy versus
execution time. They should be used where a precision of 1/HZ (e.g., 10
msec on a 100HZ machine, see hz(9)) is acceptable or where performance is
priority.
SEE ALSO
microtime(9), timecounter(9), tvtohz(9)
AUTHORS
This manual page was written by Kelly Yancey <
[email protected]>.
FreeBSD 14.1-RELEASE-p8 June 8, 2010 FreeBSD 14.1-RELEASE-p8