kvm_cptime.c revision 330897 
1/*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 2008 Yahoo!, Inc.
5 * All rights reserved.
6 * Written by: John Baldwin <jhb@FreeBSD.org>
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
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 the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the author nor the names of any co-contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD: stable/11/lib/libkvm/kvm_cptime.c 330897 2018-03-14 03:19:51Z eadler $");
35
36#include <sys/param.h>
37#include <sys/pcpu.h>
38#include <sys/resource.h>
39#include <sys/sysctl.h>
40#include <errno.h>
41#include <kvm.h>
42#include <limits.h>
43#include <stdlib.h>
44#include <string.h>
45
46#include "kvm_private.h"
47
48static struct nlist kvm_cp_time_nl[] = {
49	{ .n_name = "_cp_time" },		/* (deprecated) */
50	{ .n_name = NULL },
51};
52
53#define	NL_CP_TIME		0
54
55static int kvm_cp_time_cached;
56
57static int
58_kvm_cp_time_init(kvm_t *kd)
59{
60
61	if (kvm_nlist(kd, kvm_cp_time_nl) < 0)
62		return (-1);
63	kvm_cp_time_cached = 1;
64	return (0);
65}
66
67static int
68getsysctl(kvm_t *kd, const char *name, void *buf, size_t len)
69{
70	size_t nlen;
71
72	nlen = len;
73	if (sysctlbyname(name, buf, &nlen, NULL, 0) < 0) {
74		_kvm_err(kd, kd->program, "cannot read sysctl %s:%s", name,
75		    strerror(errno));
76		return (-1);
77	}
78	if (nlen != len) {
79		_kvm_err(kd, kd->program, "sysctl %s has unexpected size",
80		    name);
81		return (-1);
82	}
83	return (0);
84}
85
86int
87kvm_getcptime(kvm_t *kd, long *cp_time)
88{
89	struct pcpu *pc;
90	int i, j, maxcpu;
91
92	if (kd == NULL) {
93		kvm_cp_time_cached = 0;
94		return (0);
95	}
96
97	if (ISALIVE(kd))
98		return (getsysctl(kd, "kern.cp_time", cp_time, sizeof(long) *
99		    CPUSTATES));
100
101	if (!kd->arch->ka_native(kd)) {
102		_kvm_err(kd, kd->program,
103		    "cannot read cp_time from non-native core");
104		return (-1);
105	}
106
107	if (kvm_cp_time_cached == 0) {
108		if (_kvm_cp_time_init(kd) < 0)
109			return (-1);
110	}
111
112	/* If this kernel has a "cp_time[]" symbol, then just read that. */
113	if (kvm_cp_time_nl[NL_CP_TIME].n_value != 0) {
114		if (kvm_read(kd, kvm_cp_time_nl[NL_CP_TIME].n_value, cp_time,
115		    sizeof(long) * CPUSTATES) != sizeof(long) * CPUSTATES) {
116			_kvm_err(kd, kd->program, "cannot read cp_time array");
117			return (-1);
118		}
119		return (0);
120	}
121
122	/*
123	 * If we don't have that symbol, then we have to simulate
124	 * "cp_time[]" by adding up the individual times for each CPU.
125	 */
126	maxcpu = kvm_getmaxcpu(kd);
127	if (maxcpu < 0)
128		return (-1);
129	for (i = 0; i < CPUSTATES; i++)
130		cp_time[i] = 0;
131	for (i = 0; i < maxcpu; i++) {
132		pc = kvm_getpcpu(kd, i);
133		if (pc == NULL)
134			continue;
135		if (pc == (void *)-1)
136			return (-1);
137		for (j = 0; j < CPUSTATES; j++)
138			cp_time[j] += pc->pc_cp_time[j];
139		free(pc);
140	}
141	return (0);
142}
143