oshi.driver.unix.aix.perfstat.PerfstatCpu Maven / Gradle / Ivy
/*
* Copyright 2020-2022 The OSHI Project Contributors
* SPDX-License-Identifier: MIT
*/
package oshi.driver.unix.aix.perfstat;
import com.sun.jna.platform.unix.aix.Perfstat;
import com.sun.jna.platform.unix.aix.Perfstat.perfstat_cpu_t;
import com.sun.jna.platform.unix.aix.Perfstat.perfstat_cpu_total_t;
import com.sun.jna.platform.unix.aix.Perfstat.perfstat_id_t;
import oshi.annotation.concurrent.ThreadSafe;
/**
* Utility to query performance stats for cpu
*/
@ThreadSafe
public final class PerfstatCpu {
private static final Perfstat PERF = Perfstat.INSTANCE;
private PerfstatCpu() {
}
/**
* Queries perfstat_cpu_total for total CPU usage statistics
*
* @return usage statistics
*/
public static perfstat_cpu_total_t queryCpuTotal() {
perfstat_cpu_total_t cpu = new perfstat_cpu_total_t();
int ret = PERF.perfstat_cpu_total(null, cpu, cpu.size(), 1);
if (ret > 0) {
return cpu;
}
return new perfstat_cpu_total_t();
}
/**
* Queries perfstat_cpu for per-CPU usage statistics
*
* @return an array of usage statistics
*/
public static perfstat_cpu_t[] queryCpu() {
perfstat_cpu_t cpu = new perfstat_cpu_t();
// With null, null, ..., 0, returns total # of elements
int cputotal = PERF.perfstat_cpu(null, null, cpu.size(), 0);
if (cputotal > 0) {
perfstat_cpu_t[] statp = (perfstat_cpu_t[]) cpu.toArray(cputotal);
perfstat_id_t firstcpu = new perfstat_id_t(); // name is ""
int ret = PERF.perfstat_cpu(firstcpu, statp, cpu.size(), cputotal);
if (ret > 0) {
return statp;
}
}
return new perfstat_cpu_t[0];
}
/**
* Returns affinity mask from the number of CPU in the OS.
*
* @return affinity mask
*/
public static long queryCpuAffinityMask() {
int cpus = queryCpuTotal().ncpus;
if (cpus < 63) {
return (1L << cpus) - 1;
}
return cpus == 63 ? Long.MAX_VALUE : -1L;
}
}