MirBSD manpage: hz(9), profhz(9), stathz(9), tick(9), tickadj(9)

HZ(9)                         BSD Kernel Manual                          HZ(9)


     hz, tick, tickadj, stathz, profhz - system time model


     extern int hz;
     extern int tick;
     extern int tickadj;
     extern int stathz;
     extern int profhz;


     The system is driven by hardclock(9) interrupts, which occur at hz fre-
     quency, and are used to keep track of real time.

     On systems where another independent clock is available, it is set at
     stathz frequency, and used to gather timing statistics. Ideally, it would
     be better to drive stathz with a slightly randomized clock, that is still
     a fixed number on average, as this would prevent malicious processes from
     working around the scheduler. If a separate clock is not available,
     stathz is set to hz.

     If profiling is enabled, the clock normally used to drive stathz may be
     run at a higher rate profhz, which must be a multiple of stathz. This
     will give higher resolution profiling information.

     Normally, hardclock(9) increments time by tick each time it is called. If
     the system clock has drifted, adjtime(2) may be used to skew this incre-
     ment, but by no more than ten times tickadj.

     Those systems variables are available as a struct clockinfo from


     adjtime(2), clock_getres(2), sysctl(3), hardclock(9), microtime(9)

MirBSD #10-current             August 31, 1999                               1

Generated on 2021-06-15 19:39:49 by $MirOS: src/scripts/roff2htm,v 1.103 2021/01/23 20:24:35 tg Exp $ — This product includes material provided by mirabilos.

These manual pages and other documentation are copyrighted by their respective writers; their sources are available at the project’s CVSweb, AnonCVS and other mirrors. The rest is Copyright © 2002–2021 MirBSD.

This manual page’s HTML representation is supposed to be valid XHTML/1.1; if not, please send a bug report — diffs preferred.