/*
* Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
#include <fcntl.h>
#include <kstat.h>
#include <procfs.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <sys/sysinfo.h>
#include <sys/lwp.h>
#include <pthread.h>
#include <utmpx.h>
#include <dlfcn.h>
#include <sys/loadavg.h>
#include <jni.h>
#include "jvm.h"
#include "com_sun_management_UnixOperatingSystem.h"
typedef struct {
kstat_t *kstat;
uint64_t last_idle;
uint64_t last_total;
double last_ratio;
} cpuload_t;
static cpuload_t *cpu_loads = NULL;
static unsigned int num_cpus;
static kstat_ctl_t *kstat_ctrl = NULL;
static void map_cpu_kstat_counters() {
kstat_t *kstat;
int i;
// Get number of CPU(s)
if ((num_cpus = sysconf(_SC_NPROCESSORS_ONLN)) == -1) {
num_cpus = 1;
}
// Data structure for saving CPU load
if ((cpu_loads = calloc(num_cpus,sizeof(cpuload_t))) == NULL) {
return;
}
// Get kstat cpu_stat counters for every CPU
// (loop over kstat to find our cpu_stat(s)
i = 0;
for (kstat = kstat_ctrl->kc_chain; kstat != NULL; kstat = kstat->ks_next) {
if (strncmp(kstat->ks_module, "cpu_stat", 8) == 0) {
if (kstat_read(kstat_ctrl, kstat, NULL) == -1) {
// Failed to initialize kstat for this CPU so ignore it
continue;
}
if (i == num_cpus) {
// Found more cpu_stats than reported CPUs
break;
}
cpu_loads[i++].kstat = kstat;
}
}
}
static int init_cpu_kstat_counters() {
static int initialized = 0;
// Concurrence in this method is prevented by the lock in
// the calling method get_cpu_load();
if(!initialized) {
if ((kstat_ctrl = kstat_open()) != NULL) {
map_cpu_kstat_counters();
initialized = 1;
}
}
return initialized ? 0 : -1;
}
static void update_cpu_kstat_counters() {
if(kstat_chain_update(kstat_ctrl) != 0) {
free(cpu_loads);
map_cpu_kstat_counters();
}
}
int read_cpustat(cpuload_t *load, cpu_stat_t *cpu_stat) {
if (load->kstat == NULL) {
// no handle.
return -1;
}
if (kstat_read(kstat_ctrl, load->kstat, cpu_stat) == -1) {
// disabling for now, a kstat chain update is likely to happen next time
load->kstat = NULL;
return -1;
}
return 0;
}
double get_single_cpu_load(unsigned int n) {
cpuload_t *load;
cpu_stat_t cpu_stat;
uint_t *usage;
uint64_t c_idle;
uint64_t c_total;
uint64_t d_idle;
uint64_t d_total;
int i;
if (n >= num_cpus) {
return -1.0;
}
load = &cpu_loads[n];
if (read_cpustat(load, &cpu_stat) < 0) {
return -1.0;
}
usage = cpu_stat.cpu_sysinfo.cpu;
c_idle = usage[CPU_IDLE];
for (c_total = 0, i = 0; i < CPU_STATES; i++) {
c_total += usage[i];
}
// Calculate diff against previous snapshot
d_idle = c_idle - load->last_idle;
d_total = c_total - load->last_total;
/** update if weve moved */
if (d_total > 0) {
// Save current values for next time around
load->last_idle = c_idle;
load->last_total = c_total;
load->last_ratio = (double) (d_total - d_idle) / d_total;
}
return load->last_ratio;
}
int get_info(const char *path, void *info, size_t s, off_t o) {
int fd;
int ret = 0;
if ((fd = open(path, O_RDONLY)) < 0) {
return -1;
}
if (pread(fd, info, s, o) != s) {
ret = -1;
}
close(fd);
return ret;
}
#define MIN(a, b) ((a < b) ? a : b)
static pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
/**
* Return the cpu load (0-1) for proc number 'which' (or average all if which == -1)
*/
double get_cpu_load(int which) {
double load =.0;
pthread_mutex_lock(&lock);
if(init_cpu_kstat_counters()==0) {
update_cpu_kstat_counters();
if (which == -1) {
unsigned int i;
double t;
for (t = .0, i = 0; i < num_cpus; i++) {
t += get_single_cpu_load(i);
}
// Cap total systemload to 1.0
load = MIN((t / num_cpus), 1.0);
} else {
load = MIN(get_single_cpu_load(which), 1.0);
}
} else {
load = -1.0;
}
pthread_mutex_unlock(&lock);
return load;
}
/**
* Return the cpu load (0-1) for the current process (i.e the JVM)
* or -1.0 if the get_info() call failed
*/
double get_process_load(void) {
psinfo_t info;
// Get the percentage of "recent cpu usage" from all the lwp:s in the JVM:s
// process. This is returned as a value between 0.0 and 1.0 multiplied by 0x8000.
if (get_info("/proc/self/psinfo",&info.pr_pctcpu, sizeof(info.pr_pctcpu), offsetof(psinfo_t, pr_pctcpu)) == 0) {
return (double) info.pr_pctcpu / 0x8000;
}
return -1.0;
}
JNIEXPORT jdouble JNICALL
Java_com_sun_management_UnixOperatingSystem_getSystemCpuLoad
(JNIEnv *env, jobject dummy)
{
return get_cpu_load(-1);
}
JNIEXPORT jdouble JNICALL
Java_com_sun_management_UnixOperatingSystem_getProcessCpuLoad
(JNIEnv *env, jobject dummy)
{
return get_process_load();
}