lib/libkvm/kvm_util.c

   1 /*
   2  * Copyright (c) 2003, 2004 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Hiten Pandya <hmp@backplane.com>.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  *
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in
  15  *    the documentation and/or other materials provided with the
  16  *    distribution.
  17  * 3. Neither the name of The DragonFly Project nor the names of its
  18  *    contributors may be used to endorse or promote products derived
  19  *    from this software without specific, prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  * $DragonFly: src/lib/libkvm/kvm_util.c,v 1.3 2004/07/16 05:04:36 hmp Exp $
  35  */
  36
  37 /*
  38  * Useful functions that are used across the source base for
  39  * various purpose.
  40  */
  41
  42 #include <sys/param.h>
  43 #include <sys/nchstats.h>
  44 #include <sys/sysctl.h>
  45
  46 #include <stdio.h>
  47 #include <stdlib.h>
  48 #include <strings.h>
  49 #include <err.h>
  50
  51 /*
  52  * Aggregate the per-cpu counters we retrieved via sysctl(2)
  53  * to give the total across the CPUs.  Use a nasty trick to
  54  * aggregate the counters in the structure! YYY
  55  */
  56 void
  57 kvm_nch_cpuagg(struct nchstats *unagg, struct nchstats *ttl, int cpucnt)
  58 {
  59         int i, off, siz;
  60         siz = sizeof(struct nchstats);
  61
  62         if (!unagg && !ttl)
  63                 return;
  64
  65         bzero(ttl, siz);
  66
  67         /* kick hmp@ for this nasty loop! :-) */
  68         for (i = 0; i < cpucnt; ++i) {
  69                 for (off = 0; off < siz; off += sizeof(u_long)) {
  70                         *(u_long *)((char *)(*(&ttl)) + off) +=
  71                         *(u_long *)((char *)&unagg[i] + off);
  72                 }
  73         }
  74 }