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test/hotspot/jtreg/serviceability/jvmti/vthread/VThreadEventTest/VThreadEventTest.java

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@@ -26,185 +26,137 @@
   * @bug 8312174
   * @summary missing JVMTI events from vthreads parked during JVMTI attach
   * @requires vm.continuations
   * @requires vm.jvmti
   * @requires vm.compMode != "Xcomp"
+  * @modules java.base/java.lang:+open
+  * @library /test/lib
   * @run main/othervm/native
-  *     -Djdk.virtualThreadScheduler.parallelism=9
   *     -Djdk.attach.allowAttachSelf=true -XX:+EnableDynamicAgentLoading VThreadEventTest attach
   */
  
  import com.sun.tools.attach.VirtualMachine;
- import java.util.concurrent.ExecutorService;
- import java.util.concurrent.Executors;
+ import java.util.concurrent.atomic.AtomicBoolean;
  import java.util.concurrent.locks.LockSupport;
  import java.util.List;
  import java.util.ArrayList;
- 
- /*
-  * The test uses custom implementation of the CountDownLatch class.
-  * The reason is we want the state of tested thread to be predictable.
-  * With java.util.concurrent.CountDownLatch it is not clear what thread state is expected.
-  */
- class CountDownLatch {
-     private int count = 0;
- 
-     CountDownLatch(int count) {
-         this.count = count;
-     }
- 
-     public synchronized void countDown() {
-         count--;
-         notify();
-     }
- 
-     public synchronized void await() throws InterruptedException {
-         while (count > 0) {
-             wait(1);
-         }
-     }
- }
+ import jdk.test.lib.thread.VThreadRunner;
  
  public class VThreadEventTest {
-     static final int TCNT1 = 10;
-     static final int TCNT2 = 4;
-     static final int TCNT3 = 4;
-     static final int THREAD_CNT = TCNT1 + TCNT2 + TCNT3;
+     static final int PARKED_THREAD_COUNT = 4;
+     static final int SPINNING_THREAD_COUNT = 4;
  
      private static void log(String msg) { System.out.println(msg); }
  
      private static native int threadEndCount();
      private static native int threadMountCount();
      private static native int threadUnmountCount();
  
      private static volatile boolean attached;
-     private static boolean failed;
-     private static List<Thread> test1Threads = new ArrayList(TCNT1);
- 
-     private static CountDownLatch ready0 = new CountDownLatch(THREAD_CNT);
-     private static CountDownLatch ready1 = new CountDownLatch(TCNT1);
-     private static CountDownLatch ready2 = new CountDownLatch(THREAD_CNT);
-     private static CountDownLatch mready = new CountDownLatch(1);
- 
-     private static void await(CountDownLatch dumpedLatch) {
-         try {
-             dumpedLatch.await();
-         } catch (InterruptedException e) {
-             throw new RuntimeException(e);
-         }
+ 
+     // called by agent when it is initialized and has enabled events
+     static void agentStarted() {
+         attached = true;
      }
  
-     // The test1 vthreads are kept unmounted until interrupted after agent attach.
-     static final Runnable test1 = () -> {
-         synchronized (test1Threads) {
-             test1Threads.add(Thread.currentThread());
+     public static void main(String[] args) throws Exception {
+         if (Thread.currentThread().isVirtual()) {
+             System.out.println("Skipping test as current thread is a virtual thread");
+             return;
          }
-         log("test1 vthread started");
-         ready0.countDown();
-         await(mready);
-         ready1.countDown(); // to guaranty state is not State.WAITING after await(mready)
-         try {
-             Thread.sleep(20000); // big timeout to keep unmounted until interrupted
-         } catch (InterruptedException ex) {
-             // it is expected, ignore
+         VThreadRunner.ensureParallelism(SPINNING_THREAD_COUNT+1);
+ 
+         // start threads that park (unmount)
+         var threads1 = new ArrayList<Thread>();
+         for (int i = 0; i < PARKED_THREAD_COUNT; i++) {
+             var started = new AtomicBoolean();
+             var thread = Thread.startVirtualThread(() -> {
+                 started.set(true);
+                 LockSupport.park();
+             });
+ 
+             // wait for thread to start execution + park
+             while (!started.get()) {
+                 Thread.sleep(10);
+             }
+             await(thread, Thread.State.WAITING);
+             threads1.add(thread);
          }
-         ready2.countDown();
-     };
- 
-     // The test2 vthreads are kept mounted until agent attach.
-     static final Runnable test2 = () -> {
-         log("test2 vthread started");
-         ready0.countDown();
-         await(mready);
-         while (!attached) {
-             // keep mounted
+ 
+         // start threads that spin (stay mounted)
+         var threads2 = new ArrayList<Thread>();
+         for (int i = 0; i < SPINNING_THREAD_COUNT; i++) {
+             var started = new AtomicBoolean();
+             var thread = Thread.startVirtualThread(() -> {
+                 started.set(true);
+                 while (!attached) {
+                     Thread.onSpinWait();
+                 }
+             });
+ 
+             // wait for thread to start execution
+             while (!started.get()) {
+                 Thread.sleep(10);
+             }
+             threads2.add(thread);
          }
-         ready2.countDown();
-     };
- 
-     // The test3 vthreads are kept mounted until agent attach.
-     static final Runnable test3 = () -> {
-         log("test3 vthread started");
-         ready0.countDown();
-         await(mready);
+ 
+         // attach to the current VM
+         VirtualMachine vm = VirtualMachine.attach(String.valueOf(ProcessHandle.current().pid()));
+         vm.loadAgentLibrary("VThreadEventTest");
+ 
+         // wait for agent to start
          while (!attached) {
-             // keep mounted
+             Thread.sleep(10);
          }
-         LockSupport.parkNanos(10_000_000L); // will cause extra mount and unmount
-         ready2.countDown();
-     };
  
-     public static void main(String[] args) throws Exception {
-         if (Runtime.getRuntime().availableProcessors() < 8) {
-             log("WARNING: test expects at least 8 processors.");
+         // unpark the threads that were parked
+         for (Thread thread : threads1) {
+             LockSupport.unpark(thread);
          }
-         try (ExecutorService executorService = Executors.newVirtualThreadPerTaskExecutor()) {
-             for (int i = 0; i < TCNT1; i++) {
-                 executorService.execute(test1);
-             }
-             for (int i = 0; i < TCNT2; i++) {
-                 executorService.execute(test2);
-             }
-             for (int i = 0; i < TCNT3; i++) {
-                 executorService.execute(test3);
-             }
-             await(ready0);
-             mready.countDown();
-             await(ready1); // to guarantee state is not State.TIMED_WAITING after await(mready) in test1()
-             // wait for test1 threads to reach TIMED_WAITING state in sleep()
-             for (Thread t : test1Threads) {
-                 Thread.State state = t.getState();
-                 log("DBG: state: " + state);
-                 while (state != Thread.State.TIMED_WAITING) {
-                     Thread.sleep(10);
-                     state = t.getState();
-                     log("DBG: state: " + state);
-                 }
-             }
- 
-             VirtualMachine vm = VirtualMachine.attach(String.valueOf(ProcessHandle.current().pid()));
-             vm.loadAgentLibrary("VThreadEventTest");
-             Thread.sleep(200); // to allow the agent to get ready
  
-             attached = true;
-             for (Thread t : test1Threads) {
-                  t.interrupt();
-             }
-             ready2.await();
+         // wait for all threads to terminate
+         for (Thread thread : threads1) {
+             thread.join();
          }
-         // wait until all VirtualThreadEnd events have been sent
-         for (int sleepNo = 1; threadEndCount() < THREAD_CNT; sleepNo++) {
-             Thread.sleep(100);
-             if (sleepNo % 100 == 0) { // 10 sec period of waiting
-                 log("main: waited seconds: " + sleepNo/10);
-             }
+         for (Thread thread : threads2) {
+             thread.join();
          }
+ 
          int threadEndCnt = threadEndCount();
          int threadMountCnt = threadMountCount();
          int threadUnmountCnt = threadUnmountCount();
-         int threadEndExp = THREAD_CNT;
-         int threadMountExp = THREAD_CNT - TCNT2;
-         int threadUnmountExp = THREAD_CNT + TCNT3;
  
-         log("ThreadEnd cnt: "     + threadEndCnt     + " (expected: " + threadEndExp + ")");
-         log("ThreadMount cnt: "   + threadMountCnt   + " (expected: " + threadMountExp + ")");
-         log("ThreadUnmount cnt: " + threadUnmountCnt + " (expected: " + threadUnmountExp + ")");
+         int threadCount = PARKED_THREAD_COUNT + SPINNING_THREAD_COUNT;
+         log("VirtualThreadEnd events: " + threadEndCnt + ", expected: " + threadCount);
+         log("VirtualThreadMount events: " + threadMountCnt + ", expected: " + PARKED_THREAD_COUNT);
+         log("VirtualThreadUnmount events: " + threadUnmountCnt + ", expected: " + threadCount);
  
-         if (threadEndCnt != threadEndExp) {
-             log("FAILED: unexpected count of ThreadEnd events");
+         boolean failed = false;
+         if (threadEndCnt != threadCount) {
+             log("FAILED: unexpected count of VirtualThreadEnd events");
              failed = true;
          }
-         if (threadMountCnt != threadMountExp) {
-             log("FAILED: unexpected count of ThreadMount events");
+         if (threadMountCnt != PARKED_THREAD_COUNT) {
+             log("FAILED: unexpected count of VirtualThreadMount events");
              failed = true;
          }
-         if (threadUnmountCnt != threadUnmountExp) {
-             log("FAILED: unexpected count of ThreadUnmount events");
+         if (threadUnmountCnt != threadCount) {
+             log("FAILED: unexpected count of VirtualThreadUnmount events");
              failed = true;
          }
          if (failed) {
              throw new RuntimeException("FAILED: event count is wrong");
          }
      }
  
+     private static void await(Thread thread, Thread.State expectedState) throws InterruptedException {
+         Thread.State state = thread.getState();
+         while (state != expectedState) {
+             assert state != Thread.State.TERMINATED : "Thread has terminated";
+             Thread.sleep(10);
+             state = thread.getState();
+         }
+     }
+ 
  }
  
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