1/* Return frequency of ticks reported by profil. Generic version. */
2/*-
3 * Copyright (c) 1983, 1992, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 4. Neither the name of the University nor the names of its contributors
15 * may be used to endorse or promote products derived from this software
16 * without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 */
30
31
32#include <sys/types.h>
33#include <sys/time.h>
34#include <libc-internal.h>
35
36int
37__profile_frequency (void)
38{
39 /*
40 * Discover the tick frequency of the machine if something goes wrong,
41 * we return 0, an impossible hertz.
42 */
43 struct itimerval tim;
44
45 tim.it_interval.tv_sec = 0;
46 tim.it_interval.tv_usec = 1;
47 tim.it_value.tv_sec = 0;
48 tim.it_value.tv_usec = 0;
49 __setitimer(ITIMER_REAL, new: &tim, old: 0);
50 __setitimer(ITIMER_REAL, new: 0, old: &tim);
51 if (tim.it_interval.tv_usec < 2)
52 return 0;
53 return (1000000 / tim.it_interval.tv_usec);
54}
55libc_hidden_def (__profile_frequency)
56

source code of glibc/gmon/prof-freq.c