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25 package jdk.jfr.event.oldobject;
26 
27 import java.util.ArrayList;
28 import java.util.List;
29 import java.util.concurrent.BrokenBarrierException;
30 import java.util.concurrent.CyclicBarrier;
31 
32 import jdk.jfr.Recording;
33 import jdk.jfr.consumer.RecordedClass;
34 import jdk.jfr.consumer.RecordedEvent;
35 import jdk.jfr.consumer.RecordedObject;
36 import jdk.jfr.internal.test.WhiteBox;
37 import jdk.test.lib.Asserts;
38 import jdk.test.lib.jfr.EventNames;
39 import jdk.test.lib.jfr.Events;
40 
41 /**
42  * @test
43  * @key jfr
44  * @requires vm.hasJFR
45  * @requires vm.gc == "null"
46  * @library /test/lib /test/jdk
47  * @modules jdk.jfr/jdk.jfr.internal.test
48  * @run main/othervm -XX:TLABSize=2k jdk.jfr.event.oldobject.TestLargeRootSet
49  */
50 public class TestLargeRootSet {
51 
52     private static final int THREAD_COUNT = 50;
53 
54     private static class RootThread extends Thread {
55         private final CyclicBarrier barrier;
56         private int maxDepth = OldObjects.MIN_SIZE / THREAD_COUNT;
57 
58         public List<StackObject[]> temporaries = new ArrayList<>(maxDepth);
59 
RootThread(CyclicBarrier cb)60         RootThread(CyclicBarrier cb) {
61             this.barrier = cb;
62         }
63 
run()64         public void run() {
65             buildRootObjects();
66         }
67 
buildRootObjects()68         private void buildRootObjects() {
69             if (maxDepth-- > 0) {
70                 // Allocate array to trigger sampling code path for interpreter / c1
71                 StackObject[] stackObject = new StackObject[0];
72                 temporaries.add(stackObject); // make sure object escapes
73                 buildRootObjects();
74             } else {
75                 temporaries.clear();
76                 try {
77                     barrier.await(); // wait for gc
78                     barrier.await(); // wait for recording to be stopped
79                 } catch (InterruptedException e) {
80                     System.err.println("Thread was unexpected interrupted: " + e.getMessage());
81                 } catch (BrokenBarrierException e) {
82                     System.err.println("Unexpected barrier exception: " + e.getMessage());
83                 }
84                 return;
85             }
86         }
87     }
88 
89     private static class StackObject {
90     }
91 
main(String[] args)92     public static void main(String[] args) throws Exception {
93         WhiteBox.setWriteAllObjectSamples(true);
94 
95         List<RootThread> threads = new ArrayList<>();
96         try (Recording r = new Recording()) {
97             r.enable(EventNames.OldObjectSample).withStackTrace().with("cutoff", "infinity");
98             r.start();
99             CyclicBarrier cb = new CyclicBarrier(THREAD_COUNT + 1);
100             for (int i = 0; i < THREAD_COUNT; i++) {
101                 RootThread t = new RootThread(cb);
102                 t.start();
103                 if (i % 10 == 0) {
104                     // Give threads some breathing room before starting next batch
105                     Thread.sleep(100);
106                 }
107                 threads.add(t);
108             }
109             cb.await();
110             System.gc();
111             r.stop();
112             cb.await();
113             List<RecordedEvent> events = Events.fromRecording(r);
114             Events.hasEvents(events);
115             for (RecordedEvent e : events) {
116                 RecordedObject ro = e.getValue("object");
117                 RecordedClass rc = ro.getValue("type");
118                 System.out.println(rc.getName());
119                 if (rc.getName().equals(StackObject[].class.getName())) {
120                     return; // ok
121                 }
122             }
123             Asserts.fail("Could not find root object");
124         }
125     }
126 }
127 
128