2 * Copyright (c) 1983, 1993
3 * The Regents of the University of California. All rights reserved.
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32 static char sccsid[] = "@(#)hertz.c 8.1 (Berkeley) 6/6/93";
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
42 * discover the tick frequency of the machine
43 * if something goes wrong, we return 0, an impossible hertz.
52 tim.it_interval.tv_sec = 0;
53 tim.it_interval.tv_usec = 1;
54 tim.it_value.tv_sec = 0;
55 tim.it_value.tv_usec = 0;
56 setitimer(ITIMER_REAL, &tim, 0);
57 setitimer(ITIMER_REAL, 0, &tim);
58 if (tim.it_interval.tv_usec < 2)
60 return (1000000 / tim.it_interval.tv_usec);