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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,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
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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.testlibrary.Asserts;
import jdk.testlibrary.jfr.EventNames;
import jdk.testlibrary.jfr.Events;
import jdk.testlibrary.jfr.OldObjects;

/*
 * @test
 * @key jfr
 * @requires vm.gc == "null"
 * @library /lib/testlibrary
 * @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");
        }
    }
}