78 lines
2.8 KiB
Java
78 lines
2.8 KiB
Java
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/*
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* Copyright (c) 2018, 2020, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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import java.util.Random;
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import jdk.test.lib.apps.LingeredApp;
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import jdk.test.lib.Utils;
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public class LingeredAppWithNativeMethod extends LingeredApp {
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public static final String THREAD_NAME = "NoFramePointerJNIFib";
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private static final int UPPER_BOUND = 55;
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private static final int LOWER_BOUND = 40;
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private static final Random RNG = Utils.getRandomInstance();
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static {
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// JNI library compiled with no frame pointer info
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System.loadLibrary("NoFramePointer");
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}
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public void callNative() {
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// Call JNI code which does something compute
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// intensive: fibonacci
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// That is to ensure that the native bits run when
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// jstack --mixed info is to be gathered.
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// Results of fibonacci calculation from JNI are
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// reported via callback(). That's where the process
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// of calculating fibonacci restarts.
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int num = (int) (RNG.nextDouble() * UPPER_BOUND);
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while (num < LOWER_BOUND) {
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num = (int) (RNG.nextDouble() * UPPER_BOUND);
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}
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System.out.print("fib(" + num + ") = ");
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callJNI(this, num);
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}
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// Called from JNI library libNoFramePointer
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private void callback(long val) {
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System.out.println(val);
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// Call native again so as to increase chances of
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// being currently in JNI code when jstack --mixed
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// runs.
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callNative();
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}
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public static native void callJNI(Object target, int num);
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public static void main(String[] args) {
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LingeredAppWithNativeMethod app = new LingeredAppWithNativeMethod();
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Thread fibonacci = new Thread(() -> {
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app.callNative();
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});
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fibonacci.setName(THREAD_NAME);
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fibonacci.start();
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LingeredApp.main(args);
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}
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}
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