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getloadavg.c revision 1.3 
      1 /*-
      2  * Copyright (c) 1989 The Regents of the University of California.
      3  * 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[] = "from: @(#)getloadavg.c	6.2 (Berkeley) 6/29/90";*/
     36 static char rcsid[] = "$Id: getloadavg.c,v 1.3 1994/01/28 04:49:27 cgd Exp $";
     37 #endif /* LIBC_SCCS and not lint */
     38 
     39 #include <sys/types.h>
     40 #include <sys/time.h>
     41 #include <sys/resource.h>
     42 #include <sys/kinfo.h>
     43 
     44 /*
     45  *  getloadavg() -- Get system load averages.
     46  *
     47  *  Put `nelem' samples into `loadavg' array.
     48  *  Return number of samples retrieved, or -1 on error.
     49  */
     50 getloadavg(loadavg, nelem)
     51 	double loadavg[];
     52 	int nelem;
     53 {
     54 	int needed, err, i;
     55 	struct loadavg averunnable;
     56 
     57 	needed = getkerninfo(KINFO_LOADAVG, NULL, NULL, 0);
     58 	if (needed != sizeof(struct loadavg))
     59 		return -1;
     60 
     61 	err = getkerninfo(KINFO_LOADAVG, &averunnable, &needed, 0);
     62 	if (err != 0 || needed != sizeof(struct loadavg))
     63 		return -1;
     64 
     65 	if (nelem > 3)
     66 		nelem = 3;
     67 	for (i = 0; i < nelem; i++)
     68 		loadavg[i] = (double) averunnable.ldavg[i] / averunnable.fscale;
     69 	return nelem;
     70 }
     71