getloadavg.c revision 1573 
1/*-
2 * Copyright (c) 1989, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#if defined(LIBC_SCCS) && !defined(lint)
35static char sccsid[] = "@(#)getloadavg.c	8.1 (Berkeley) 6/4/93";
36#endif /* LIBC_SCCS and not lint */
37
38#include <sys/param.h>
39#include <sys/time.h>
40#include <sys/resource.h>
41#include <sys/sysctl.h>
42#include <vm/vm_param.h>
43
44#include <stdlib.h>
45
46/*
47 * getloadavg() -- Get system load averages.
48 *
49 * Put `nelem' samples into `loadavg' array.
50 * Return number of samples retrieved, or -1 on error.
51 */
52int
53getloadavg(loadavg, nelem)
54	double loadavg[];
55	int nelem;
56{
57	struct loadavg loadinfo;
58	int i, mib[2];
59	size_t size;
60
61	mib[0] = CTL_VM;
62	mib[1] = VM_LOADAVG;
63	size = sizeof(loadinfo);
64	if (sysctl(mib, 2, &loadinfo, &size, NULL, 0) < 0)
65		return (-1);
66
67	nelem = MIN(nelem, sizeof(loadinfo.ldavg) / sizeof(fixpt_t));
68	for (i = 0; i < nelem; i++)
69		loadavg[i] = (double) loadinfo.ldavg[i] / loadinfo.fscale;
70	return (nelem);
71}
72