JNIEXPORT jdouble JNICALL
Java_com_sun_management_UnixOperatingSystem_getProcessCpuLoad
(JNIEnv *env, jobject dummy)
{
// This code is influenced by the darwin top source
struct task_basic_info_64 task_info_data;
struct task_thread_times_info thread_info_data;
struct timeval user_timeval, system_timeval, task_timeval;
struct timeval now;
mach_port_t task = mach_task_self();
kern_return_t kr;
static jlong last_task_time = 0;
static jlong last_time = 0;
mach_msg_type_number_t thread_info_count = TASK_THREAD_TIMES_INFO_COUNT;
kr = task_info(task,
TASK_THREAD_TIMES_INFO,
(task_info_t)&thread_info_data,
&thread_info_count);
if (kr != KERN_SUCCESS) {
// Most likely cause: |task| is a zombie.
return -1;
}
mach_msg_type_number_t count = TASK_BASIC_INFO_64_COUNT;
kr = task_info(task,
TASK_BASIC_INFO_64,
(task_info_t)&task_info_data,
&count);
if (kr != KERN_SUCCESS) {
// Most likely cause: |task| is a zombie.
return -1;
}
/* Set total_time. */
// thread info contains live time...
TIME_VALUE_TO_TIMEVAL(&thread_info_data.user_time, &user_timeval);
TIME_VALUE_TO_TIMEVAL(&thread_info_data.system_time, &system_timeval);
timeradd(&user_timeval, &system_timeval, &task_timeval);
// ... task info contains terminated time.
TIME_VALUE_TO_TIMEVAL(&task_info_data.user_time, &user_timeval);
TIME_VALUE_TO_TIMEVAL(&task_info_data.system_time, &system_timeval);
timeradd(&user_timeval, &task_timeval, &task_timeval);
timeradd(&system_timeval, &task_timeval, &task_timeval);
if (gettimeofday(&now, NULL) < 0) {
return -1;
}
jint ncpus = JVM_ActiveProcessorCount();
jlong time = TIME_VALUE_TO_MICROSECONDS(now) * ncpus;
jlong task_time = TIME_VALUE_TO_MICROSECONDS(task_timeval);
if ((last_task_time == 0) || (last_time == 0)) {
// First call, just set the last values.
last_task_time = task_time;
last_time = time;
// return 0 since we have no data, not -1 which indicates error
return 0;
}
jlong task_time_delta = task_time - last_task_time;
jlong time_delta = time - last_time;
if (time_delta == 0) {
return -1;
}
jdouble cpu = (jdouble) task_time_delta / time_delta;
last_task_time = task_time;
last_time = time;
return cpu;
}
JNIEXPORT jint JNICALL
Java_sun_management_VMManagementImpl_getAvailableProcessors
(JNIEnv *env, jobject dummy)
{
return JVM_ActiveProcessorCount();
}
