test/hotspot/jtreg/runtime/handshake/HandshakeWalkSuspendExitTest.java
changeset 52341 2b58b8e1d28f
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/hotspot/jtreg/runtime/handshake/HandshakeWalkSuspendExitTest.java	Wed Oct 31 08:09:45 2018 +0100
@@ -0,0 +1,93 @@
+/*
+ * Copyright (c) 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.
+ *
+ * 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.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+/*
+ * @test HandshakeWalkSuspendExitTest
+ * @summary This test tries to stress the handshakes with new and exiting threads while suspending them.
+ * @library /testlibrary /test/lib
+ * @build HandshakeWalkSuspendExitTest
+ * @run driver ClassFileInstaller sun.hotspot.WhiteBox
+ *                              sun.hotspot.WhiteBox$WhiteBoxPermission
+ * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI HandshakeWalkSuspendExitTest
+ */
+
+import jdk.test.lib.Asserts;
+import sun.hotspot.WhiteBox;
+
+public class HandshakeWalkSuspendExitTest  implements Runnable {
+
+    static final int _test_threads = 8;
+    static final int _test_exit_threads = 128;
+    static Thread[] _threads = new Thread[_test_threads];
+    static volatile boolean exit_now = false;
+    static java.util.concurrent.Semaphore _sem = new java.util.concurrent.Semaphore(0);
+
+    @Override
+    public void run() {
+        WhiteBox wb = WhiteBox.getWhiteBox();
+        while (!exit_now) {
+            _sem.release();
+            // We only suspend threads on even index and not ourself.
+            // Otherwise we can accidentially suspend all threads.
+            for (int i = 0; i < _threads.length; i += 2) {
+                wb.handshakeWalkStack(null /* ignored */, true /* stackwalk all threads */);
+                if (Thread.currentThread() != _threads[i]) {
+                    _threads[i].suspend();
+                    _threads[i].resume();
+                }
+            }
+            for (int i = 0; i < _threads.length; i += 2) {
+                wb.handshakeWalkStack(_threads[i] /* thread to stackwalk */, false /* stackwalk one thread */);
+                if (Thread.currentThread() != _threads[i]) {
+                    _threads[i].suspend();
+                    _threads[i].resume();
+                }
+            }
+        }
+    }
+
+    public static void main(String... args) throws Exception {
+        HandshakeWalkSuspendExitTest test = new HandshakeWalkSuspendExitTest();
+
+        for (int i = 0; i < _threads.length; i++) {
+            _threads[i] = new Thread(test);
+            _threads[i].start();
+        }
+        for (int i = 0; i < _test_threads; i++) {
+            _sem.acquire();
+        }
+        Thread[] exit_threads = new Thread[_test_exit_threads];
+        for (int i = 0; i < _test_exit_threads; i++) {
+            exit_threads[i] = new Thread(new Runnable() { public void run() {} });
+            exit_threads[i].start();
+        }
+        exit_now = true;
+        for (int i = 0; i < _threads.length; i++) {
+            _threads[i].join();
+        }
+        for (int i = 0; i < exit_threads.length; i++) {
+            exit_threads[i].join();
+        }
+    }
+}