lib/libc/gen/getloadavg.c

   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  * @(#)getloadavg.c     8.1 (Berkeley) 6/4/93
  34  * $DragonFly: src/lib/libc/gen/getloadavg.c,v 1.4 2005/04/30 23:28:57 hmp Exp $
  35  */
  36
  37 #include <sys/param.h>
  38 #include <sys/time.h>
  39 #include <sys/resource.h>
  40 #include <sys/sysctl.h>
  41
  42 #include <stdlib.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 int
  51 getloadavg(double loadavg[], int nelem)
  52 {
  53         struct loadavg loadinfo;
  54         size_t i, size;
  55
  56         size = sizeof(loadinfo);
  57         if (sysctlbyname("vm.loadavg", &loadinfo, &size, NULL, 0) < 0)
  58                 return (-1);
  59
  60         nelem = MIN(nelem, sizeof(loadinfo.ldavg) / sizeof(fixpt_t));
  61         for (i = 0; i < nelem; i++)
  62                 loadavg[i] = (double) loadinfo.ldavg[i] / loadinfo.fscale;
  63         return (nelem);
  64 }