Example usage for java.lang.management ThreadMXBean isThreadCpuTimeSupported

Introduction

In this page you can find the example usage for java.lang.management ThreadMXBean isThreadCpuTimeSupported.

Prototype

public boolean isThreadCpuTimeSupported();

Source Link

Document

Tests if the Java virtual machine implementation supports CPU time measurement for any thread.

Usage

From source file:eu.planets_project.tb.gui.backing.exp.ExpTypeMigrate.java

public static void main(String args[]) {

    Properties p = System.getProperties();

    ByteArrayOutputStream byos = new ByteArrayOutputStream();
    try {//from w  w  w .ja  va  2  s  .  c o  m
        p.storeToXML(byos, "Automatically generated for PLANETS Service ", "UTF-8");
        String res = byos.toString("UTF-8");
        System.out.println(res);
    } catch (IOException e) {
        e.printStackTrace();
    }

    // This.
    List<String> pl = new ArrayList<String>();
    for (Object key : p.keySet()) {
        pl.add((String) key);
    }
    Collections.sort(pl);

    //
    for (String key : pl) {
        System.out.println(key + " = " + p.getProperty(key));
    }

    /*
     * http://java.sun.com/j2se/1.5.0/docs/api/java/lang/management/ThreadMXBean.html#getCurrentThreadCpuTime()
     * 
     * http://www.java-forums.org/new-java/5303-how-determine-cpu-usage-using-java.html
     * 
     */

    ThreadMXBean TMB = ManagementFactory.getThreadMXBean();
    int mscale = 1000000;
    long time = 0, time2 = 0;
    long cput = 0, cput2 = 0;
    double cpuperc = -1;

    //Begin loop.
    for (int i = 0; i < 10; i++) {

        if (TMB.isThreadCpuTimeSupported()) {
            if (!TMB.isThreadCpuTimeEnabled()) {
                TMB.setThreadCpuTimeEnabled(true);
            }

            //                if(new Date().getTime() * mscale - time > 1000000000) //Reset once per second
            //                {
            System.out.println("Resetting...");
            time = System.currentTimeMillis() * mscale;
            cput = TMB.getCurrentThreadCpuTime();
            //                cput = TMB.getCurrentThreadUserTime();
            //                }

        }

        //Do cpu intensive stuff
        for (int k = 0; k < 10; k++) {
            for (int j = 0; j < 100000; j++) {
                double a = Math.pow(i, j);
                double b = a / j + Math.random();
                a = b * Math.random();
                b = a * Math.random();
            }

            try {
                Thread.sleep(10);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }

        }

        if (TMB.isThreadCpuTimeSupported()) {
            //                if(new Date().getTime() * mscale - time != 0) {
            cput2 = TMB.getCurrentThreadCpuTime();
            System.out.println("cpu: " + (cput2 - cput) / (1000.0 * mscale));
            //                cput2 = TMB.getCurrentThreadUserTime();

            time2 = System.currentTimeMillis() * mscale;
            System.out.println("time: " + (time2 - time) / (1000.0 * mscale));

            cpuperc = 100.0 * (cput2 - cput) / (double) (time2 - time);
            System.out.println("cpu perc = " + cpuperc);
            //                }
        }
        //End Loop
    }
    System.out.println("Done.");
}

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From source file:net.bull.javamelody.internal.model.JavaInformations.java

public static List<ThreadInformations> buildThreadInformationsList() {
    final ThreadMXBean threadBean = ManagementFactory.getThreadMXBean();
    final Map<Thread, StackTraceElement[]> stackTraces = Thread.getAllStackTraces();
    final List<Thread> threads = new ArrayList<Thread>(stackTraces.keySet());

    // si "1.6.0_01".compareTo(Parameters.JAVA_VERSION) > 0;
    // on rcuprait les threads sans stack trace en contournant bug 6434648 avant 1.6.0_01
    // http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6434648
    // hormis pour le thread courant qui obtient sa stack trace diffremment sans le bug
    //      threads = getThreadsFromThreadGroups();
    //      final Thread currentThread = Thread.currentThread();
    //      stackTraces = Collections.singletonMap(currentThread, currentThread.getStackTrace());

    final boolean cpuTimeEnabled = threadBean.isThreadCpuTimeSupported() && threadBean.isThreadCpuTimeEnabled();
    final long[] deadlockedThreads = getDeadlockedThreads(threadBean);
    final List<ThreadInformations> threadInfosList = new ArrayList<ThreadInformations>(threads.size());
    // hostAddress rcupr ici car il peut y avoir plus de 20000 threads
    final String hostAddress = Parameters.getHostAddress();
    for (final Thread thread : threads) {
        final StackTraceElement[] stackTraceElements = stackTraces.get(thread);
        final List<StackTraceElement> stackTraceElementList = stackTraceElements == null ? null
                : new ArrayList<StackTraceElement>(Arrays.asList(stackTraceElements));
        final long cpuTimeMillis;
        final long userTimeMillis;
        if (cpuTimeEnabled) {
            cpuTimeMillis = threadBean.getThreadCpuTime(thread.getId()) / 1000000;
            userTimeMillis = threadBean.getThreadUserTime(thread.getId()) / 1000000;
        } else {/* w  w w.j  a v a  2s.c o m*/
            cpuTimeMillis = -1;
            userTimeMillis = -1;
        }
        final boolean deadlocked = deadlockedThreads != null
                && Arrays.binarySearch(deadlockedThreads, thread.getId()) >= 0;
        // stackTraceElementList est une ArrayList et non unmodifiableList pour lisibilit xml
        threadInfosList.add(new ThreadInformations(thread, stackTraceElementList, cpuTimeMillis, userTimeMillis,
                deadlocked, hostAddress));
    }
    // on retourne ArrayList et non unmodifiableList pour lisibilit du xml par xstream
    return threadInfosList;
}

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