MICROUPTIME(9)

MICROUPTIME(9) | 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 <kbyanc@posi.net>.

June 8, 2010 | NetBSD 7.1