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 * Copyright (c) 2015, 2018, 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,

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 *

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package jdk.jfr.event.oldobject;

import java.util.ArrayList;

import java.util.List;

import java.util.concurrent.BrokenBarrierException;

import java.util.concurrent.CyclicBarrier;

import jdk.jfr.Recording;

import jdk.jfr.consumer.RecordedClass;

import jdk.jfr.consumer.RecordedEvent;

import jdk.jfr.consumer.RecordedObject;

import jdk.jfr.internal.test.WhiteBox;

import jdk.test.lib.Asserts;

import jdk.test.lib.jfr.EventNames;

import jdk.test.lib.jfr.Events;

/*

 * @test

 * @key jfr

 * @requires vm.gc == "null"

 * @library /test/lib /test/jdk

 * @modules jdk.jfr/jdk.jfr.internal.test

 * @run main/othervm -XX:TLABSize=2k -XX:-FastTLABRefill jdk.jfr.event.oldobject.TestLargeRootSet

 */

public class TestLargeRootSet {

    private static final int THREAD_COUNT = 50;

    private static class RootThread extends Thread {

        private final CyclicBarrier barrier;

        private int maxDepth = OldObjects.MIN_SIZE / THREAD_COUNT;

        public List<StackObject[]> temporaries = new ArrayList<>(maxDepth);

        RootThread(CyclicBarrier cb) {

            this.barrier = cb;

        }

        public void run() {

            buildRootObjects();

        }

        private void buildRootObjects() {

            if (maxDepth-- > 0) {

                // Allocate array to trigger sampling code path for interpreter / c1

                StackObject[] stackObject = new StackObject[0];

                temporaries.add(stackObject); // make sure object escapes

                buildRootObjects();

            } else {

                temporaries.clear();

                try {

                    barrier.await(); // wait for gc

                    barrier.await(); // wait for recording to be stopped

                } catch (InterruptedException e) {

                    System.err.println("Thread was unexpected interrupted: " + e.getMessage());

                } catch (BrokenBarrierException e) {

                    System.err.println("Unexpected barrier exception: " + e.getMessage());

                }

                return;

            }

        }

    }

    private static class StackObject {

    }

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

        WhiteBox.setWriteAllObjectSamples(true);

        List<RootThread> threads = new ArrayList<>();

        try (Recording r = new Recording()) {

            r.enable(EventNames.OldObjectSample).withStackTrace().with("cutoff", "infinity");

            r.start();

            CyclicBarrier cb = new CyclicBarrier(THREAD_COUNT + 1);

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

                RootThread t = new RootThread(cb);

                t.start();

                if (i % 10 == 0) {

                    // Give threads some breathing room before starting next batch

                    Thread.sleep(100);

                }

                threads.add(t);

            }

            cb.await();

            System.gc();

            r.stop();

            cb.await();

            List<RecordedEvent> events = Events.fromRecording(r);

            Events.hasEvents(events);

            for (RecordedEvent e : events) {

                RecordedObject ro = e.getValue("object");

                RecordedClass rc = ro.getValue("type");

                System.out.println(rc.getName());

                if (rc.getName().equals(StackObject[].class.getName())) {

                    return; // ok

                }

            }

            Asserts.fail("Could not find root object");

        }

    }

}