1 /*
2 * Copyright (c) 2016, 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 import java.io.PrintStream;
25 import java.util.ArrayList;
26 import java.util.List;
27 import java.util.Map;
28 import java.util.Random;
29 import sun.hotspot.WhiteBox;
30
31 /*
32 * @test TestMultiThreadStressRSet.java
33 * @key stress
34 * @requires vm.gc.G1
35 * @requires os.maxMemory > 2G
36 * @requires vm.opt.MaxGCPauseMillis == "null"
37 *
38 * @summary Stress G1 Remembered Set using multiple threads
39 * @modules java.base/jdk.internal.misc
40 * @library /test/lib /testlibrary
41 * @build sun.hotspot.WhiteBox
42 * @run main ClassFileInstaller sun.hotspot.WhiteBox
43 * sun.hotspot.WhiteBox$WhiteBoxPermission
44 * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI
45 * -XX:+UseG1GC -XX:G1SummarizeRSetStatsPeriod=1 -Xlog:gc
46 * -Xmx500m -XX:G1HeapRegionSize=1m -XX:MaxGCPauseMillis=1000 TestMultiThreadStressRSet 10 4
47 *
48 * @run main/othervm -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI
49 * -XX:+UseG1GC -XX:G1SummarizeRSetStatsPeriod=100 -Xlog:gc
50 * -Xmx1G -XX:G1HeapRegionSize=8m -XX:MaxGCPauseMillis=1000 TestMultiThreadStressRSet 60 16
51 *
52 * @run main/othervm/timeout=700 -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI
53 * -XX:+UseG1GC -XX:G1SummarizeRSetStatsPeriod=100 -Xlog:gc
54 * -Xmx500m -XX:G1HeapRegionSize=1m -XX:MaxGCPauseMillis=1000 TestMultiThreadStressRSet 600 32
55 */
56 public class TestMultiThreadStressRSet {
57
58 private static final Random RND = new Random(2015 * 2016);
59 private static final WhiteBox WB = WhiteBox.getWhiteBox();
60 private static final int REF_SIZE = WB.getHeapOopSize();
61 private static final int REGION_SIZE = WB.g1RegionSize();
62
63 // How many regions to use for the storage
64 private static final int STORAGE_REGIONS = 20;
65
66 // Size a single obj in the storage
67 private static final int OBJ_SIZE = 1024;
68
69 // How many regions of young/old gen to use in the BUFFER
70 private static final int BUFFER_YOUNG_REGIONS = 60;
71 private static final int BUFFER_OLD_REGIONS = 40;
72
73 // Total number of objects in the storage.
74 private final int N;
75
76 // The storage of byte[]
77 private final List<Object> STORAGE;
78
79 // Where references to the Storage will be stored
80 private final List<Object[]> BUFFER;
81
82 // The length of a buffer element.
83 // RSet deals with "cards" (areas of 512 bytes), not with single refs
84 // So, to affect the RSet the BUFFER refs should be allocated in different
85 // memory cards.
86 private final int BUF_ARR_LEN = 100 * (512 / REF_SIZE);
87
88 // Total number of objects in the young/old buffers
89 private final int YOUNG;
90 private final int OLD;
91
92 // To cause Remembered Sets change their coarse level the test uses a window
93 // within STORAGE. All the BUFFER elements refer to only STORAGE objects
94 // from the current window. The window is defined by a range.
95 // The first element has got the index: 'windowStart',
96 // the last one: 'windowStart + windowSize - 1'
97 // The window is shifting periodically.
98 private int windowStart;
99 private final int windowSize;
100
101 // Counter of created worker threads
102 private int counter = 0;
103
104 private volatile String errorMessage = null;
105 private volatile boolean isEnough = false;
106
107 public static void main(String args[]) {
108 if (args.length != 2) {
109 throw new IllegalArgumentException("TEST BUG: wrong arg count " + args.length);
110 }
111 long time = Long.parseLong(args[0]);
112 int threads = Integer.parseInt(args[1]);
113 new TestMultiThreadStressRSet().test(time * 1000, threads);
114 }
115
116 /**
117 * Initiates test parameters, fills out the STORAGE and BUFFER.
118 */
119 public TestMultiThreadStressRSet() {
120
121 N = (REGION_SIZE - 1) * STORAGE_REGIONS / OBJ_SIZE + 1;
122 STORAGE = new ArrayList<>(N);
123 int bytes = OBJ_SIZE - 20;
124 for (int i = 0; i < N - 1; i++) {
125 STORAGE.add(new byte[bytes]);
126 }
127 STORAGE.add(new byte[REGION_SIZE / 2 + 100]); // humongous
128 windowStart = 0;
129 windowSize = REGION_SIZE / OBJ_SIZE;
130
131 BUFFER = new ArrayList<>();
132 int sizeOfBufferObject = 20 + REF_SIZE * BUF_ARR_LEN;
133 OLD = REGION_SIZE * BUFFER_OLD_REGIONS / sizeOfBufferObject;
134 YOUNG = REGION_SIZE * BUFFER_YOUNG_REGIONS / sizeOfBufferObject;
135 for (int i = 0; i < OLD + YOUNG; i++) {
136 BUFFER.add(new Object[BUF_ARR_LEN]);
137 }
138 }
139
140 /**
141 * Does the testing. Steps:
142 * <ul>
143 * <li> starts the Shifter thread
144 * <li> during the given time starts new Worker threads, keeping the number
145 * of live thread under limit.
146 * <li> stops the Shifter thread
147 * </ul>
148 *
149 * @param timeInMillis how long to stress
150 * @param maxThreads the maximum number of Worker thread working together.
151 */
152 public void test(long timeInMillis, int maxThreads) {
153 if (timeInMillis <= 0 || maxThreads <= 0) {
154 throw new IllegalArgumentException("TEST BUG: be positive!");
155 }
156 System.out.println("%% Time to work: " + timeInMillis / 1000 + "s");
157 System.out.println("%% Number of threads: " + maxThreads);
158 long finish = System.currentTimeMillis() + timeInMillis;
159 Shifter shift = new Shifter(this, 1000, (int) (windowSize * 0.9));
160 shift.start();
161 for (int i = 0; i < maxThreads; i++) {
162 new Worker(this, 100).start();
163 }
164 try {
165 while (System.currentTimeMillis() < finish && errorMessage == null) {
166 Thread.sleep(100);
167 }
168 } catch (Throwable t) {
169 printAllStackTraces(System.err);
170 t.printStackTrace(System.err);
171 this.errorMessage = t.getMessage();
172 } finally {
173 isEnough = true;
174 }
175 System.out.println("%% Total work cycles: " + counter);
176 if (errorMessage != null) {
177 throw new RuntimeException(errorMessage);
178 }
179 }
180
181 /**
182 * Returns an element from from the BUFFER (an object array) to keep
183 * references to the storage.
184 *
185 * @return an Object[] from buffer.
186 */
187 private Object[] getFromBuffer() {
188 int index = counter % (OLD + YOUNG);
189 synchronized (BUFFER) {
190 if (index < OLD) {
191 if (counter % 100 == (counter / 100) % 100) {
192 // need to generate garbage in the old gen to provoke mixed GC
193 return replaceInBuffer(index);
194 } else {
195 return BUFFER.get(index);
196 }
197 } else {
198 return replaceInBuffer(index);
199 }
200 }
201 }
202
203 private Object[] replaceInBuffer(int index) {
204 Object[] objs = new Object[BUF_ARR_LEN];
205 BUFFER.set(index, objs);
206 return objs;
207 }
208
209 /**
210 * Returns a random object from the current window within the storage.
211 * A storage element with index from windowStart to windowStart+windowSize.
212 *
213 * @return a random element from the current window within the storage.
214 */
215 private Object getRandomObject() {
216 int index = (windowStart + RND.nextInt(windowSize)) % N;
217 return STORAGE.get(index);
218 }
219
220 private static void printAllStackTraces(PrintStream ps) {
221 Map<Thread, StackTraceElement[]> traces = Thread.getAllStackTraces();
222 for (Thread t : traces.keySet()) {
223 ps.println(t.toString() + " " + t.getState());
224 for (StackTraceElement traceElement : traces.get(t)) {
225 ps.println("\tat " + traceElement);
226 }
227 }
228 }
229
230 /**
231 * Thread to create a number of references from BUFFER to STORAGE.
232 */
233 private static class Worker extends Thread {
234
235 final TestMultiThreadStressRSet boss;
236 final int refs; // number of refs to OldGen
237
238 /**
239 * @param boss the tests
240 * @param refsToOldGen how many references to the OldGen to create
241 */
242 Worker(TestMultiThreadStressRSet boss, int refsToOldGen) {
243 this.boss = boss;
244 this.refs = refsToOldGen;
245 }
246
247 @Override
248 public void run() {
249 try {
250 while (!boss.isEnough) {
251 Object[] objs = boss.getFromBuffer();
252 int step = objs.length / refs;
253 for (int i = 0; i < refs; i += step) {
254 objs[i] = boss.getRandomObject();
255 }
256 boss.counter++;
257 }
258 } catch (Throwable t) {
259 t.printStackTrace(System.out);
260 boss.errorMessage = t.getMessage();
261 }
262 }
263 }
264
265 /**
266 * Periodically shifts the current STORAGE window, removing references
267 * in BUFFER that refer to objects outside the window.
268 */
269 private static class Shifter extends Thread {
270
271 final TestMultiThreadStressRSet boss;
272 final int sleepTime;
273 final int shift;
274
275 Shifter(TestMultiThreadStressRSet boss, int sleepTime, int shift) {
276 this.boss = boss;
277 this.sleepTime = sleepTime;
278 this.shift = shift;
279 }
280
281 @Override
282 public void run() {
283 try {
284 while (!boss.isEnough) {
285 Thread.sleep(sleepTime);
286 boss.windowStart += shift;
287 for (int i = 0; i < boss.OLD; i++) {
288 Object[] objs = boss.BUFFER.get(i);
289 for (int j = 0; j < objs.length; j++) {
290 objs[j] = null;
291 }
292 }
293 if (!WB.g1InConcurrentMark()) {
294 System.out.println("%% start CMC");
295 WB.g1StartConcMarkCycle();
296 } else {
297 System.out.println("%% CMC is already in progress");
298 }
299 }
300 } catch (Throwable t) {
301 t.printStackTrace(System.out);
302 boss.errorMessage = t.getMessage();
303 }
304 }
305 }
306 }
307