1 /*
2 * Copyright (c) 2016, 2021, 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 package gc.stress;
25
26 import java.io.PrintStream;
27 import java.util.ArrayList;
28 import java.util.List;
29 import java.util.Map;
30 import java.util.Random;
31 import sun.hotspot.WhiteBox;
32 import jdk.test.lib.Utils;
33
34 /*
35 * @test TestMultiThreadStressRSet.java
36 * @key stress randomness
37 * @requires vm.gc.G1
38 * @requires os.maxMemory > 2G
39 * @requires vm.opt.MaxGCPauseMillis == "null"
40 *
41 * @summary Stress G1 Remembered Set using multiple threads
42 * @modules java.base/jdk.internal.misc
43 * @library /test/lib
44 * @build sun.hotspot.WhiteBox
45 * @run driver jdk.test.lib.helpers.ClassFileInstaller sun.hotspot.WhiteBox
46 * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI
47 * -XX:+UseG1GC -XX:G1SummarizeRSetStatsPeriod=1 -Xlog:gc
48 * -Xmx500m -XX:G1HeapRegionSize=1m -XX:MaxGCPauseMillis=1000 gc.stress.TestMultiThreadStressRSet 10 4
49 *
50 * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI
51 * -XX:+UseG1GC -XX:G1SummarizeRSetStatsPeriod=100 -Xlog:gc
52 * -Xmx1100M -XX:G1HeapRegionSize=8m -XX:MaxGCPauseMillis=1000 gc.stress.TestMultiThreadStressRSet 60 16
53 *
54 * @run main/othervm/timeout=700 -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI
55 * -XX:+UseG1GC -XX:G1SummarizeRSetStatsPeriod=100 -Xlog:gc
56 * -Xmx500m -XX:G1HeapRegionSize=1m -XX:MaxGCPauseMillis=1000 gc.stress.TestMultiThreadStressRSet 600 32
57 */
58 public class TestMultiThreadStressRSet {
59
60 private static final WhiteBox WB = WhiteBox.getWhiteBox();
61 private static final int REF_SIZE = WB.getHeapOopSize();
62 private static final int REGION_SIZE = WB.g1RegionSize();
63
64 // How many regions to use for the storage
65 private static final int STORAGE_REGIONS = 20;
66
67 // Size a single obj in the storage
68 private static final int OBJ_SIZE = 1024;
69
70 // How many regions of young/old gen to use in the BUFFER
71 private static final int BUFFER_YOUNG_REGIONS = 60;
72 private static final int BUFFER_OLD_REGIONS = 40;
73
74 // Total number of objects in the storage.
75 private final int N;
76
77 // The storage of byte[]
78 private final List<Object> STORAGE;
79
80 // Where references to the Storage will be stored
81 private final List<Object[]> BUFFER;
82
83 // The length of a buffer element.
84 // RSet deals with "cards" (areas of 512 bytes), not with single refs
85 // So, to affect the RSet the BUFFER refs should be allocated in different
86 // memory cards.
87 private final int BUF_ARR_LEN = 100 * (512 / REF_SIZE);
88
89 // Total number of objects in the young/old buffers
90 private final int YOUNG;
91 private final int OLD;
92
93 // To cause Remembered Sets change their coarse level the test uses a window
94 // within STORAGE. All the BUFFER elements refer to only STORAGE objects
95 // from the current window. The window is defined by a range.
96 // The first element has got the index: 'windowStart',
97 // the last one: 'windowStart + windowSize - 1'
98 // The window is shifting periodically.
99 private int windowStart;
100 private final int windowSize;
101
102 // Counter of created worker threads
103 private int counter = 0;
104
105 private volatile String errorMessage = null;
106 private volatile boolean isEnough = false;
107
108 public static void main(String args[]) {
109 if (args.length != 2) {
110 throw new IllegalArgumentException("TEST BUG: wrong arg count " + args.length);
111 }
112 long time = Long.parseLong(args[0]);
113 int threads = Integer.parseInt(args[1]);
114 new TestMultiThreadStressRSet().test(time * 1000, threads);
115 }
116
117 /**
118 * Initiates test parameters, fills out the STORAGE and BUFFER.
119 */
120 public TestMultiThreadStressRSet() {
121
122 N = (REGION_SIZE - 1) * STORAGE_REGIONS / OBJ_SIZE + 1;
123 STORAGE = new ArrayList<>(N);
124 int bytes = OBJ_SIZE - 20;
125 for (int i = 0; i < N - 1; i++) {
126 STORAGE.add(new byte[bytes]);
127 }
128 STORAGE.add(new byte[REGION_SIZE / 2 + 100]); // humongous
129 windowStart = 0;
130 windowSize = REGION_SIZE / OBJ_SIZE;
131
132 BUFFER = new ArrayList<>();
133 int sizeOfBufferObject = 20 + REF_SIZE * BUF_ARR_LEN;
134 OLD = REGION_SIZE * BUFFER_OLD_REGIONS / sizeOfBufferObject;
135 YOUNG = REGION_SIZE * BUFFER_YOUNG_REGIONS / sizeOfBufferObject;
136 for (int i = 0; i < OLD + YOUNG; i++) {
137 BUFFER.add(new Object[BUF_ARR_LEN]);
138 }
139 }
140
141 /**
142 * Does the testing. Steps:
143 * <ul>
144 * <li> starts the Shifter thread
145 * <li> during the given time starts new Worker threads, keeping the number
146 * of live thread under limit.
147 * <li> stops the Shifter thread
148 * </ul>
149 *
150 * @param timeInMillis how long to stress
151 * @param maxThreads the maximum number of Worker thread working together.
152 */
153 public void test(long timeInMillis, int maxThreads) {
154 if (timeInMillis <= 0 || maxThreads <= 0) {
155 throw new IllegalArgumentException("TEST BUG: be positive!");
156 }
157 System.out.println("%% Time to work: " + timeInMillis / 1000 + "s");
158 System.out.println("%% Number of threads: " + maxThreads);
159 long finish = System.currentTimeMillis() + timeInMillis;
160 Shifter shift = new Shifter(this, 1000, (int) (windowSize * 0.9));
161 shift.start();
162 for (int i = 0; i < maxThreads; i++) {
163 new Worker(this, 100).start();
164 }
165 try {
166 while (System.currentTimeMillis() < finish && errorMessage == null) {
167 Thread.sleep(100);
168 }
169 } catch (Throwable t) {
170 printAllStackTraces(System.err);
171 t.printStackTrace(System.err);
172 this.errorMessage = t.getMessage();
173 } finally {
174 isEnough = true;
175 }
176 System.out.println("%% Total work cycles: " + counter);
177 if (errorMessage != null) {
178 throw new RuntimeException(errorMessage);
179 }
180 }
181
182 /**
183 * Returns an element from from the BUFFER (an object array) to keep
184 * references to the storage.
185 *
186 * @return an Object[] from buffer.
187 */
188 private Object[] getFromBuffer() {
189 int index = counter % (OLD + YOUNG);
190 synchronized (BUFFER) {
191 if (index < OLD) {
192 if (counter % 100 == (counter / 100) % 100) {
193 // need to generate garbage in the old gen to provoke mixed GC
194 return replaceInBuffer(index);
195 } else {
196 return BUFFER.get(index);
197 }
198 } else {
199 return replaceInBuffer(index);
200 }
201 }
202 }
203
204 private Object[] replaceInBuffer(int index) {
205 Object[] objs = new Object[BUF_ARR_LEN];
206 BUFFER.set(index, objs);
207 return objs;
208 }
209
210 /**
211 * Returns a random object from the current window within the storage.
212 * A storage element with index from windowStart to windowStart+windowSize.
213 *
214 * @return a random element from the current window within the storage.
215 */
216 private Object getRandomObject(Random rnd) {
217 int index = (windowStart + rnd.nextInt(windowSize)) % N;
218 return STORAGE.get(index);
219 }
220
221 private static void printAllStackTraces(PrintStream ps) {
222 Map<Thread, StackTraceElement[]> traces = Thread.getAllStackTraces();
223 for (Thread t : traces.keySet()) {
224 ps.println(t.toString() + " " + t.getState());
225 for (StackTraceElement traceElement : traces.get(t)) {
226 ps.println("\tat " + traceElement);
227 }
228 }
229 }
230
231 /**
232 * Thread to create a number of references from BUFFER to STORAGE.
233 */
234 private static class Worker extends Thread {
235 final Random rnd;
236 final TestMultiThreadStressRSet boss;
237 final int refs; // number of refs to OldGen
238
239 /**
240 * @param boss the tests
241 * @param refsToOldGen how many references to the OldGen to create
242 */
243 Worker(TestMultiThreadStressRSet boss, int refsToOldGen) {
244 this.boss = boss;
245 this.refs = refsToOldGen;
246 this.rnd = new Random(Utils.getRandomInstance().nextLong());
247 }
248
249 @Override
250 public void run() {
251 try {
252 while (!boss.isEnough) {
253 Object[] objs = boss.getFromBuffer();
254 int step = objs.length / refs;
255 for (int i = 0; i < refs; i += step) {
256 objs[i] = boss.getRandomObject(rnd);
257 }
258 boss.counter++;
259 }
260 } catch (Throwable t) {
261 t.printStackTrace(System.out);
262 boss.errorMessage = t.getMessage();
263 }
264 }
265 }
266
267 /**
268 * Periodically shifts the current STORAGE window, removing references
269 * in BUFFER that refer to objects outside the window.
270 */
271 private static class Shifter extends Thread {
272
273 final TestMultiThreadStressRSet boss;
274 final int sleepTime;
275 final int shift;
276
277 Shifter(TestMultiThreadStressRSet boss, int sleepTime, int shift) {
278 this.boss = boss;
279 this.sleepTime = sleepTime;
280 this.shift = shift;
281 }
282
283 @Override
284 public void run() {
285 try {
286 while (!boss.isEnough) {
287 Thread.sleep(sleepTime);
288 boss.windowStart += shift;
289 for (int i = 0; i < boss.OLD; i++) {
290 Object[] objs = boss.BUFFER.get(i);
291 for (int j = 0; j < objs.length; j++) {
292 objs[j] = null;
293 }
294 }
295 if (!WB.g1InConcurrentMark()) {
296 System.out.println("%% start CMC");
297 WB.g1StartConcMarkCycle();
298 } else {
299 System.out.println("%% CMC is already in progress");
300 }
301 }
302 } catch (Throwable t) {
303 t.printStackTrace(System.out);
304 boss.errorMessage = t.getMessage();
305 }
306 }
307 }
308 }
309