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 * 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,

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 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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package jdk.jfr.event.runtime;

import static jdk.test.lib.Asserts.assertGreaterThan;

import static jdk.test.lib.Asserts.assertTrue;

import java.lang.management.ManagementFactory;

import java.time.Duration;

import java.util.Collections;

import java.util.List;

import java.util.Random;

import java.util.concurrent.CountDownLatch;

import com.sun.management.ThreadMXBean;

import jdk.jfr.Recording;

import jdk.jfr.consumer.RecordedEvent;

import jdk.jfr.consumer.RecordedThread;

import jdk.test.lib.jfr.EventNames;

import jdk.test.lib.jfr.Events;

/*

 * @test

 * @key jfr

 * @library /test/lib

 * @modules jdk.jfr

 *          jdk.management

 *

 * @run main/othervm -XX:-UseTLAB jdk.jfr.event.runtime.TestThreadAllocationEvent

 */

/**

 * The test will create a few threads that will allocate memory for a short time.

 * During this time a number of thread_allocation events will be generated.

 * The test will verify:

 * 1. That number of allocated bytes is not decreasing for a thread.

 *  - This assumption is only true when not using TLABs. For this reason the

 *    test is run with -XX:-UseTLAB. When using TLABs, the code calculating the

 *    allocated bytes is using the current TLAB to do as good of an approximation

 *    as possible, but this introduces a race which might double count the current

 *    TLAB when it is full and in the middle of being switched out.

 * 2. That sum of allocated bytes approximately matches value in ThreadMXBean.

 */

public class TestThreadAllocationEvent {

    private static final String EVENT_NAME = EventNames.ThreadAllocationStatistics;

    private static final String testThreadName = "testThread-";

    private static final long eventPeriodMillis = 50;

    // The value in both the JFR event and in the ThreadMXBean is documented as

    // an "approximation" of number of bytes allocated.

    // To not give any false errors, we allow an error margin of 5 mb.

    // The test will typically allocate over 600 mb, so 5 mb is an error of less than 1%.

    private static final long allowedTotalAllocatedDiff = 5000000;

    public static void main(String[] args) throws Throwable {

        Recording recording = new Recording();

        recording.enable(EVENT_NAME).withPeriod(Duration.ofMillis(eventPeriodMillis));

        recording.start();

        AllocatorThread[] threads = new AllocatorThread[4];

        CountDownLatch allocationsDoneLatch = new CountDownLatch(threads.length);

        for (int i = 0; i < threads.length; i++) {

            threads[i] = new AllocatorThread(allocationsDoneLatch, 1000 * (i + 1));

            threads[i].setName(testThreadName + i);

            threads[i].setDaemon(true);

            threads[i].start();

        }

        // Take regular measurements while the threads are allocating memory.

        // Stop measurement when all threads are ready.

        try {

            allocationsDoneLatch.await();

        } catch (InterruptedException e) {

            e.printStackTrace();

        }

        // Verify that number of allocated bytes is not decreasing.

        recording.stop();

        verifyAllocationsNotDecreasing(Events.fromRecording(recording), threads);

        // Now allocations are done and threads are waiting to die.

        // Make a new instant recording to get total number of allocated bytes.

        // The reason for this extra recording is to make sure we get a JFR event

        // after all allocations are done so we can compare the JFR value with

        // the value reported by ThreadMXBean.

        recording = new Recording();

        recording.enable(EVENT_NAME);

        recording.start();

        recording.stop();

        verifyTotalAllocated(Events.fromRecording(recording), threads);

    }

    /**

     * Verify that the allocated value never decreases.

     * We only compare our own allocator threads. The reason for that is that other threads

     * may start/stop at any time, and we do not know if other thread names are unique.

     */

     private static void verifyAllocationsNotDecreasing(List<RecordedEvent> events, AllocatorThread[] threads) {

         Collections.sort(events, (u,v) -> u.getEndTime().compareTo(v.getEndTime()));

         long[] prevAllocated = new long[threads.length];

         for (RecordedEvent event : events) {

             RecordedThread rt = Events.assertField(event, "thread").notNull().getValue(); // Check that we have a thread.

             String name = rt.getJavaName();

             for (int i = 0; i < threads.length; i++) {

                 if (name.equals(threads[i].getName())) {

                     long curr = Events.assertField(event, "allocated").atLeast(prevAllocated[i]).getValue();

                     prevAllocated[i] = curr;

                 }

             }

         }

         for (int i = 0; i < threads.length; i++) {

             assertGreaterThan(prevAllocated[i], 0L, "No allocations for thread " + threads[i].getName());

         }

     }

     /**

      * Verify that total allocated bytes in JFR event approximately matches the value in ThreadMXBean.

      */

    private static void verifyTotalAllocated(List<RecordedEvent> events, AllocatorThread[] threads) {

        boolean[] isEventFound = new boolean[threads.length];

        for (RecordedEvent event : events) {

            RecordedThread rt = Events.assertField(event, "thread").notNull().getValue();

            String name = rt.getJavaName();

            for (int i = 0; i < threads.length; ++i) {

                if (name.equals(threads[i].getName())) {

                    System.out.println("Event:" + event);

                    long maxAllowed = threads[i].totalAllocated + allowedTotalAllocatedDiff;

                    long minAllowed = Math.max(0, threads[i].totalAllocated - allowedTotalAllocatedDiff);

                    Events.assertField(event, "allocated").atLeast(minAllowed).atMost(maxAllowed);

                    isEventFound[i] = true;

                }

            }

        }

        for (int i = 0; i < threads.length; ++i) {

            assertTrue(isEventFound[i], "No event for thread id " + i);

        }

    }

    /**

     * Thread that does a number of allocations and records total number of

     * bytes allocated as reported by ThreadMXBean.

     */

    public static class AllocatorThread extends Thread {

        private volatile long totalAllocated = -1;

        private final int averageAllocationSize;

        public byte[] buffer;

        private final CountDownLatch allocationsDoneLatch;

        public AllocatorThread(CountDownLatch allocationsDoneLatch, int averageAllocationSize) {

            this.allocationsDoneLatch = allocationsDoneLatch;

            this.averageAllocationSize = averageAllocationSize;

        }

        @Override

        public void run() {

            Random rand = new Random();

            int allocationSizeBase = averageAllocationSize / 2;

            int allocationSizeRandom = averageAllocationSize;

            for (int batches=0; batches<100; batches++) {

                for (int i=0; i<1500; i++) {

                    buffer = new byte[rand.nextInt(allocationSizeRandom) + allocationSizeBase];

                }

                try {

                    // No need to allocate too much data between JFR events, so do a short sleep.

                    Thread.sleep(eventPeriodMillis / 5);

                } catch (InterruptedException e) {

                    e.printStackTrace();

                }

            }

            totalAllocated = getThreadAllocatedBytes();

            allocationsDoneLatch.countDown();

            // Need to keep thread alive so we can get the final JFR event.

            // This is a daemon thread, so it will finish when the main thread finishes.

            while (true) {

                Thread.yield();

            }

        }

        private long getThreadAllocatedBytes() {

            ThreadMXBean bean = (ThreadMXBean) ManagementFactory.getThreadMXBean();

            return bean.getThreadAllocatedBytes(Thread.currentThread().getId());

        }

    }

}