1*8a16b7a1SPedro F. Giffuni /*-
2*8a16b7a1SPedro F. Giffuni * SPDX-License-Identifier: BSD-3-Clause
3*8a16b7a1SPedro F. Giffuni *
49b50d902SRodney W. Grimes * Copyright (c) 1983, 1993
59b50d902SRodney W. Grimes * The Regents of the University of California. All rights reserved.
69b50d902SRodney W. Grimes *
79b50d902SRodney W. Grimes * Redistribution and use in source and binary forms, with or without
89b50d902SRodney W. Grimes * modification, are permitted provided that the following conditions
99b50d902SRodney W. Grimes * are met:
109b50d902SRodney W. Grimes * 1. Redistributions of source code must retain the above copyright
119b50d902SRodney W. Grimes * notice, this list of conditions and the following disclaimer.
129b50d902SRodney W. Grimes * 2. Redistributions in binary form must reproduce the above copyright
139b50d902SRodney W. Grimes * notice, this list of conditions and the following disclaimer in the
149b50d902SRodney W. Grimes * documentation and/or other materials provided with the distribution.
15fbbd9655SWarner Losh * 3. Neither the name of the University nor the names of its contributors
169b50d902SRodney W. Grimes * may be used to endorse or promote products derived from this software
179b50d902SRodney W. Grimes * without specific prior written permission.
189b50d902SRodney W. Grimes *
199b50d902SRodney W. Grimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
209b50d902SRodney W. Grimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
219b50d902SRodney W. Grimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
229b50d902SRodney W. Grimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
239b50d902SRodney W. Grimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
249b50d902SRodney W. Grimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
259b50d902SRodney W. Grimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
269b50d902SRodney W. Grimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
279b50d902SRodney W. Grimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
289b50d902SRodney W. Grimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
299b50d902SRodney W. Grimes * SUCH DAMAGE.
309b50d902SRodney W. Grimes */
319b50d902SRodney W. Grimes
3297fa9b77SPhilippe Charnier #include <sys/cdefs.h>
339b50d902SRodney W. Grimes #include <sys/time.h>
349b50d902SRodney W. Grimes
359b50d902SRodney W. Grimes /*
369b50d902SRodney W. Grimes * discover the tick frequency of the machine
379b50d902SRodney W. Grimes * if something goes wrong, we return 0, an impossible hertz.
389b50d902SRodney W. Grimes */
399b50d902SRodney W. Grimes #define HZ_WRONG 0
409b50d902SRodney W. Grimes
41af2637dbSPhilippe Charnier int hertz(void);
42af2637dbSPhilippe Charnier
43bd6da6a5SStefan Farfeleder int
hertz(void)44bd6da6a5SStefan Farfeleder hertz(void)
459b50d902SRodney W. Grimes {
469b50d902SRodney W. Grimes struct itimerval tim;
479b50d902SRodney W. Grimes
489b50d902SRodney W. Grimes tim.it_interval.tv_sec = 0;
499b50d902SRodney W. Grimes tim.it_interval.tv_usec = 1;
509b50d902SRodney W. Grimes tim.it_value.tv_sec = 0;
519b50d902SRodney W. Grimes tim.it_value.tv_usec = 0;
529b50d902SRodney W. Grimes setitimer(ITIMER_REAL, &tim, 0);
539b50d902SRodney W. Grimes setitimer(ITIMER_REAL, 0, &tim);
549b50d902SRodney W. Grimes if (tim.it_interval.tv_usec < 2)
559b50d902SRodney W. Grimes return(HZ_WRONG);
569b50d902SRodney W. Grimes return (1000000 / tim.it_interval.tv_usec);
579b50d902SRodney W. Grimes }
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