nanouptime(9) - NetBSD Manual Pages

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MICROUPTIME(9)         NetBSD 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 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

     bintime(9), getbintime(9), getmicrotime(9), getnanotime(9), hz(9),
     microtime(9), nanotime(9), timecounter(9), tvtohz(9)


AUTHORS

     This manual page was written by Kelly Yancey <kbyanc@posi.net>.

NetBSD 5.1                     November 24, 2008                    NetBSD 5.1