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getloadavg.c revision 1.4 
      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)
     35 static 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  */
     52 int
     53 getloadavg(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