1 /*
2 * Copyright (c) 2017, 2020, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24 /*
25 * @test
26 * @key randomness
27 * @bug 8059022
28 * @modules java.base/jdk.internal.misc:+open
29 * @summary Validate barriers after Unsafe getReference, CAS and swap (GetAndSet)
30 * @requires vm.gc.Z & !vm.graal.enabled
31 * @library /test/lib
32 * @run main/othervm -XX:+UseZGC -XX:+UnlockDiagnosticVMOptions -XX:+ZVerifyViews -XX:ZCollectionInterval=1 -XX:-CreateCoredumpOnCrash -XX:CompileCommand=dontinline,*::mergeImpl* compiler.gcbarriers.UnsafeIntrinsicsTest
33 */
34
35 package compiler.gcbarriers;
36
37 import java.lang.reflect.Field;
38 import java.util.ArrayList;
39 import java.util.Random;
40 import jdk.test.lib.Utils;
41 import sun.misc.Unsafe;
42
43 public class UnsafeIntrinsicsTest {
44
45 /*
46 * This test triggers the loadbarriers by allocating a lot, keeping the objects alive and then
47 * letting them die in a way that maximizes fragmentation.
48 *
49 * All subtests (OperationType's) could run in parallel.
50 */
51
52 static int node_count = 133700;
53 static int thread_count = 4;
54 static int time = Integer.getInteger("time", 4); // seconds per subtest
55
56 static Runner r = new Runner(null, 1, 1, Runner.OperationType.CAS);
57
58 static Node first_node;
59 int epoch = 0;
60
61 public static void main(String[] args) {
62 UnsafeIntrinsicsTest t = new UnsafeIntrinsicsTest();
63
64 t.testWithLocalData(Runner.OperationType.CAS);
65 t.testWithLocalData(Runner.OperationType.Weak_CAS);
66 t.testWithLocalData(Runner.OperationType.CMPX);
67
68 t.testWithSharedData(Runner.OperationType.Swap);
69 t.testWithSharedData(Runner.OperationType.Load);
70 }
71
72 public UnsafeIntrinsicsTest() {
73
74 }
75
76 public void testWithLocalData(Runner.OperationType optype) {
77 System.out.println("Testing " + optype.name() + " with " + thread_count +" thread and " + node_count + " nodes");
78
79 // start mutator threads
80 ArrayList<Thread> thread_list = new ArrayList<Thread>();
81 Random r = Utils.getRandomInstance();
82 for (int i = 0; i < thread_count; i++) {
83
84 setup(); // each thread has its own circle of nodes
85 Thread t = new Thread(new Runner(first_node, time, r.nextLong(), optype));
86 t.start();
87 thread_list.add(t);
88 }
89
90 waitForCompletion(thread_list);
91 countNodes();
92 }
93
94 public void testWithSharedData(Runner.OperationType optype) {
95 System.out.println("Testing " + optype.name() + " with " + thread_count +" thread and " + node_count + " nodes");
96
97 setup(); // All nodes are shared between threads
98 ArrayList<Thread> thread_list = new ArrayList<Thread>();
99 Random r = Utils.getRandomInstance();
100 for (int i = 0; i < thread_count; i++) {
101 Thread t = new Thread(new Runner(first_node, time, r.nextLong(), optype));
102 t.start();
103 thread_list.add(t);
104 }
105
106 waitForCompletion(thread_list);
107 countNodes();
108 }
109
110 public void waitForCompletion(ArrayList<Thread> thread_list) {
111 // do some waiting
112 try {
113 Thread.sleep(time*1000);
114 } catch (InterruptedException e) {
115 e.printStackTrace();
116 }
117
118 // wait for all thread to terminate
119 for (int i = 0; i < thread_count; i++) {
120 try {
121 thread_list.get(i).join();
122 } catch (InterruptedException e) {
123 e.printStackTrace();
124 }
125 }
126 }
127
128 void countNodes() {
129 epoch++;
130 int count = 0;
131 Node node = first_node;
132 while (node.number() < epoch) {
133 node.setNumber(epoch);
134 count++;
135 node = node.next();
136 }
137 System.out.println("Program end, found " + count + " nodes");
138 }
139
140 // Create a circular linked list
141 public void setup() {
142 first_node = new Node();
143 Node last_node = first_node;
144 for (int i = 0; i < node_count; i++) {
145 last_node = new Node(last_node);
146 }
147 first_node.setNext(last_node);
148 }
149 }
150
151 class Runner implements Runnable {
152
153 OperationType type;
154 Node current;
155 Random r;
156 long time;
157 long seed;
158
159 long milage = 0;
160 long created = 0;
161 long skipped = 0;
162 int iterations = 0;
163
164 static final jdk.internal.misc.Unsafe UNSAFE;
165 static final long offset;
166
167 public enum OperationType {
168 Load("Load"),
169 Swap("Swap"),
170 CAS("CAS"),
171 Weak_CAS("Weak-CAS"),
172 CMPX("CMPX");
173
174 private String name;
175 private OperationType(String name) { this.name = name; }
176 }
177
178 static {
179 try {
180 Field f = jdk.internal.misc.Unsafe.class.getDeclaredField("theUnsafe");
181 f.setAccessible(true);
182 UNSAFE = (jdk.internal.misc.Unsafe) f.get(null);
183 offset = UNSAFE.objectFieldOffset(Node.class.getDeclaredField("next"));
184 } catch (Exception e) {
185 throw new RuntimeException("Unable to get Unsafe instance.", e);
186 }
187 }
188
189 public Runner(Node start, int testtime, long seed, OperationType type) {
190 current = start;
191 time = testtime*1000000000L;
192 r = new Random(seed);
193 this.type = type;
194 }
195
196 @Override
197 public void run() {
198 long starttime = System.nanoTime();
199 while((System.nanoTime() - starttime) < time) {
200 iterations++;
201 // Run a bit
202 int run_length = r.nextInt() & 0xfff;
203 for (int i = 0; i < run_length; i++) {
204 current = current.next();
205 milage++;
206 }
207 // find a start node
208 Node startNode = current;
209 Node expectedNext = startNode.next;
210
211 // Run a bit more
212 int skip_length = (r.nextInt() & 0xff) + 1;
213 for (int i = 0; i < skip_length; i++) {
214 current = current.next();
215 skipped++;
216 }
217
218 // create a branch
219 int branch_length = (r.nextInt() & 0xff) + 1;
220 created += branch_length;
221 Node head = makeBranch(current, branch_length);
222
223 // complete circle, but continue to run on old path
224 boolean test_fail = ((iterations & 0x1) == 0);
225 Node current = merge(startNode, expectedNext, head, test_fail);
226 }
227 System.out.println("Milage: " + milage + " Skipped: " + skipped + " Created: " + created + " iterations: " + iterations);
228 }
229
230 /*
231 * The reason for the duplicated code that is wrapping the unsafe operations is that we want
232 * to test the operations individually. They must not interfere with each other - checking a field
233 * will heal that reference and no operation after can trigger the barrier.
234 *
235 * All mergeImpl*-method are prevented from being inlined.
236 */
237
238 private Node merge(Node startNode, Node expectedNext, Node head, boolean test_fail) {
239 switch (type) {
240 case Load:
241 return mergeImplLoad(startNode, expectedNext, head);
242 case Swap:
243 return mergeImplSwap(startNode, expectedNext, head);
244 case CAS:
245 if (test_fail) {
246 return mergeImplCASFail(startNode, expectedNext, head);
247 } else {
248 return mergeImplCAS(startNode, expectedNext, head);
249 }
250 case Weak_CAS:
251 if (test_fail) {
252 return mergeImplWeakCASFail(startNode, expectedNext, head);
253 } else {
254 return mergeImplWeakCAS(startNode, expectedNext, head);
255 }
256 case CMPX:
257 if (test_fail) {
258 return mergeImplCMPXFail(startNode, expectedNext, head);
259 } else {
260 return mergeImplCMPX(startNode, expectedNext, head);
261 }
262 default:
263 throw new Error("Unimplemented");
264 }
265 }
266
267 private Node mergeImplLoad(Node startNode, Node expectedNext, Node head) {
268 // Atomic load version
269 Node temp = (Node) UNSAFE.getReference(startNode, offset);
270 startNode.setNext(head);
271 return temp;
272 }
273
274 private Node mergeImplSwap(Node startNode, Node expectedNext, Node head) {
275 // Swap version
276 return (Node) UNSAFE.getAndSetReference(startNode, offset, head);
277 }
278
279 private Node mergeImplCAS(Node startNode, Node expectedNext, Node head) {
280 // CAS - should always be true within a single thread - no other thread can have overwritten
281 if (!UNSAFE.compareAndSetReference(startNode, offset, expectedNext, head)) {
282 throw new Error("CAS should always succeed on thread local objects, check you barrier implementation");
283 }
284 return expectedNext; // continue on old circle
285 }
286
287 private Node mergeImplCASFail(Node startNode, Node expectedNext, Node head) {
288 // Force a fail
289 if (UNSAFE.compareAndSetReference(startNode, offset, "fail", head)) {
290 throw new Error("This CAS should always fail, check you barrier implementation");
291 }
292 if (startNode.next() != expectedNext) {
293 throw new Error("Shouldn't have changed");
294 }
295 return current;
296 }
297
298 private Node mergeImplWeakCAS(Node startNode, Node expectedNext, Node head) {
299 // Weak CAS - should always be true within a single thread - no other thread can have overwritten
300 if (!UNSAFE.weakCompareAndSetReference(startNode, offset, expectedNext, head)) {
301 throw new Error("Weak CAS should always succeed on thread local objects, check you barrier implementation");
302 }
303 return expectedNext; // continue on old circle
304 }
305
306 private Node mergeImplWeakCASFail(Node startNode, Node expectedNext, Node head) {
307 // Force a fail
308 if (UNSAFE.weakCompareAndSetReference(startNode, offset, "fail", head)) {
309 throw new Error("This weak CAS should always fail, check you barrier implementation");
310 }
311 if (startNode.next() != expectedNext) {
312 throw new Error("Shouldn't have changed");
313 }
314 return current;
315 }
316
317 private Node mergeImplCMPX(Node startNode, Node expectedNext, Node head) {
318 // CmpX - should always be true within a single thread - no other thread can have overwritten
319 Object res = UNSAFE.compareAndExchangeReference(startNode, offset, expectedNext, head);
320 if (!res.equals(expectedNext)) {
321 throw new Error("Fail CmpX should always succeed on thread local objects, check you barrier implementation");
322 }
323 return expectedNext; // continue on old circle
324 }
325
326 private Node mergeImplCMPXFail(Node startNode, Node expectedNext, Node head) {
327 Object res = UNSAFE.compareAndExchangeReference(startNode, offset, head, head);
328 if (startNode.next() != expectedNext) {
329 throw new Error("Shouldn't have changed");
330 }
331 if (head == expectedNext) {
332 throw new Error("Test malfunction");
333 }
334 if (!res.equals(expectedNext)) {
335 throw new Error("This CmpX should have returned 'expectedNext' when it failed");
336 }
337 if (res.equals(head)) {
338 throw new Error("This CmpX shouldn't have returned head when it failed. count: "+ iterations);
339 }
340
341 return current;
342 }
343
344 // Create a new branch that will replace a part of the circle
345 public Node makeBranch(Node end_node, int count) {
346 Node head = end_node;
347 for (int i = 0; i < count; i++) {
348 head = new Node(head);
349 }
350 return head;
351 }
352 }
353
354 class Node {
355 Node next;
356 int number = 0;
357
358 public int number() {
359 return number;
360 }
361
362 public void setNumber(int v) {
363 number = v;
364 }
365
366 public Node() {
367 }
368
369 public Node(Node link) {
370 next = link;
371 }
372
373 public void setNext(Node next) {
374 this.next = next;
375 }
376 public Node next() {
377 return next;
378 }
379 }