xref: /dragonfly/lib/libkvm/kvm_util.c (revision ed183f8c)
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 
35 /*
36  * Useful functions that are used across the source base for
37  * various purpose.
38  */
39 
40 #include <sys/param.h>
41 #include <sys/nchstats.h>
42 #include <sys/sysctl.h>
43 #include <strings.h>
44 
45 #include "kvm.h"
46 
47 /*
48  * Aggregate the per-cpu counters we retrieved via sysctl(2)
49  * to give the total across the CPUs.  Use a nasty trick to
50  * aggregate the counters in the structure! YYY
51  */
52 void
53 kvm_nch_cpuagg(struct nchstats *unagg, struct nchstats *ttl, int cpucnt)
54 {
55 	int i, off, siz;
56 	siz = sizeof(struct nchstats);
57 
58 	if (!unagg && !ttl)
59 		return;
60 
61 	bzero(ttl, siz);
62 
63 	/* kick hmp@ for this nasty loop! :-) */
64 	for (i = 0; i < cpucnt; ++i) {
65 		for (off = 0; off < siz; off += sizeof(u_long)) {
66 			*(u_long *)((char *)(*(&ttl)) + off) +=
67 			*(u_long *)((char *)&unagg[i] + off);
68 		}
69 	}
70 }
71