1 /*
2 * Copyright (c) 2015, 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 TestGCOld
26 * @key gc
27 * @key stress
28 * @requires vm.gc=="null"
29 * @summary Stress the GC by trying to make old objects more likely to be garbage than young objects.
30 * @run main/othervm -Xmx384M -XX:+UseSerialGC TestGCOld 50 1 20 10 10000
31 * @run main/othervm -Xmx384M -XX:+UseParallelGC TestGCOld 50 1 20 10 10000
32 * @run main/othervm -Xmx384M -XX:+UseParallelGC -XX:-UseParallelOldGC TestGCOld 50 1 20 10 10000
33 * @run main/othervm -Xmx384M -XX:+UseConcMarkSweepGC TestGCOld 50 1 20 10 10000
34 * @run main/othervm -Xmx384M -XX:+UseG1GC TestGCOld 50 1 20 10 10000
35 * @run main/othervm -Xms64m -Xmx128m -XX:+UseG1GC -XX:+UseDynamicNumberOfGCThreads -Xlog:gc,gc+task=trace TestGCOld 50 5 20 1 5000
36 * @run main/othervm -Xms64m -Xmx128m -XX:+UseG1GC -XX:+UseDynamicNumberOfGCThreads -XX:+UnlockDiagnosticVMOptions -XX:+InjectGCWorkerCreationFailure -Xlog:gc,gc+task=trace TestGCOld 50 5 20 1 5000
37 */
38
39 import java.text.*;
40 import java.util.Random;
41
42 class TreeNode {
43 public TreeNode left, right;
44 public int val; // will always be the height of the tree
45 }
46
47
48 /* Args:
49 live-data-size: in megabytes (approximate, will be rounded down).
50 work: units of mutator non-allocation work per byte allocated,
51 (in unspecified units. This will affect the promotion rate
52 printed at the end of the run: more mutator work per step implies
53 fewer steps per second implies fewer bytes promoted per second.)
54 short/long ratio: ratio of short-lived bytes allocated to long-lived
55 bytes allocated.
56 pointer mutation rate: number of pointer mutations per step.
57 steps: number of steps to do.
58 */
59
60 public class TestGCOld {
61
62 // Command-line parameters.
63
64 private static int size, workUnits, promoteRate, ptrMutRate, steps;
65
66 // Constants.
67
68 private static final int MEG = 1000000;
69 private static final int INSIGNIFICANT = 999; // this many bytes don't matter
70 private static final int BYTES_PER_WORD = 4;
71 private static final int BYTES_PER_NODE = 20; // bytes per TreeNode
72 private static final int WORDS_DEAD = 100; // size of young garbage object
73
74 private final static int treeHeight = 14;
75 private final static long treeSize = heightToBytes(treeHeight);
76
77 private static final String msg1
78 = "Usage: java TestGCOld <size> <work> <ratio> <mutation> <steps>";
79 private static final String msg2
80 = " where <size> is the live storage in megabytes";
81 private static final String msg3
82 = " <work> is the mutator work per step (arbitrary units)";
83 private static final String msg4
84 = " <ratio> is the ratio of short-lived to long-lived allocation";
85 private static final String msg5
86 = " <mutation> is the mutations per step";
87 private static final String msg6
88 = " <steps> is the number of steps";
89
90 // Counters (and global variables that discourage optimization)
91
92 private static long youngBytes = 0; // total young bytes allocated
93 private static long nodes = 0; // total tree nodes allocated
94 private static long actuallyMut = 0; // pointer mutations in old trees
95 private static long mutatorSum = 0; // checksum to discourage optimization
96 public static int[] aexport; // exported array to discourage opt
97
98 // Global variables.
99
100 private static TreeNode[] trees;
101 private static int where = 0; // roving index into trees
102 private static Random rnd = new Random();
103
104 // Returns the height of the given tree.
105
106 private static int height (TreeNode t) {
107 if (t == null) {
108 return 0;
109 }
110 else {
111 return 1 + Math.max (height (t.left), height (t.right));
112 }
113 }
114
115 // Returns the length of the shortest path in the given tree.
116
117 private static int shortestPath (TreeNode t) {
118 if (t == null) {
119 return 0;
120 }
121 else {
122 return 1 + Math.min (shortestPath (t.left), shortestPath (t.right));
123 }
124 }
125
126 // Returns the number of nodes in a balanced tree of the given height.
127
128 private static long heightToNodes (int h) {
129 if (h == 0) {
130 return 0;
131 }
132 else {
133 long n = 1;
134 while (h > 1) {
135 n = n + n;
136 h = h - 1;
137 }
138 return n + n - 1;
139 }
140 }
141
142 // Returns the number of bytes in a balanced tree of the given height.
143
144 private static long heightToBytes (int h) {
145 return BYTES_PER_NODE * heightToNodes (h);
146 }
147
148 // Returns the height of the largest balanced tree
149 // that has no more than the given number of nodes.
150
151 private static int nodesToHeight (long nodes) {
152 int h = 1;
153 long n = 1;
154 while (n + n - 1 <= nodes) {
155 n = n + n;
156 h = h + 1;
157 }
158 return h - 1;
159 }
160
161 // Returns the height of the largest balanced tree
162 // that occupies no more than the given number of bytes.
163
164 private static int bytesToHeight (long bytes) {
165 return nodesToHeight (bytes / BYTES_PER_NODE);
166 }
167
168 // Returns a newly allocated balanced binary tree of height h.
169
170 private static TreeNode makeTree(int h) {
171 if (h == 0) return null;
172 else {
173 TreeNode res = new TreeNode();
174 nodes++;
175 res.left = makeTree(h-1);
176 res.right = makeTree(h-1);
177 res.val = h;
178 return res;
179 }
180 }
181
182 // Allocates approximately size megabytes of trees and stores
183 // them into a global array.
184
185 private static void init() {
186 int ntrees = (int) ((size * MEG) / treeSize);
187 trees = new TreeNode[ntrees];
188
189 System.err.println("Allocating " + ntrees + " trees.");
190 System.err.println(" (" + (ntrees * treeSize) + " bytes)");
191 for (int i = 0; i < ntrees; i++) {
192 trees[i] = makeTree(treeHeight);
193 // doYoungGenAlloc(promoteRate*ntrees*treeSize, WORDS_DEAD);
194 }
195 System.err.println(" (" + nodes + " nodes)");
196
197 /* Allow any in-progress GC to catch up... */
198 // try { Thread.sleep(20000); } catch (InterruptedException x) {}
199 }
200
201 // Confirms that all trees are balanced and have the correct height.
202
203 private static void checkTrees() {
204 int ntrees = trees.length;
205 for (int i = 0; i < ntrees; i++) {
206 TreeNode t = trees[i];
207 int h1 = height(t);
208 int h2 = shortestPath(t);
209 if ((h1 != treeHeight) || (h2 != treeHeight)) {
210 System.err.println("*****BUG: " + h1 + " " + h2);
211 }
212 }
213 }
214
215 // Called only by replaceTree (below) and by itself.
216
217 private static void replaceTreeWork(TreeNode full, TreeNode partial, boolean dir) {
218 boolean canGoLeft = full.left != null && full.left.val > partial.val;
219 boolean canGoRight = full.right != null && full.right.val > partial.val;
220 if (canGoLeft && canGoRight) {
221 if (dir)
222 replaceTreeWork(full.left, partial, !dir);
223 else
224 replaceTreeWork(full.right, partial, !dir);
225 } else if (!canGoLeft && !canGoRight) {
226 if (dir)
227 full.left = partial;
228 else
229 full.right = partial;
230 } else if (!canGoLeft) {
231 full.left = partial;
232 } else {
233 full.right = partial;
234 }
235 }
236
237 // Given a balanced tree full and a smaller balanced tree partial,
238 // replaces an appropriate subtree of full by partial, taking care
239 // to preserve the shape of the full tree.
240
241 private static void replaceTree(TreeNode full, TreeNode partial) {
242 boolean dir = (partial.val % 2) == 0;
243 actuallyMut++;
244 replaceTreeWork(full, partial, dir);
245 }
246
247 // Allocates approximately n bytes of long-lived storage,
248 // replacing oldest existing long-lived storage.
249
250 private static void oldGenAlloc(long n) {
251 int full = (int) (n / treeSize);
252 long partial = n % treeSize;
253 // System.out.println("In oldGenAlloc, doing " + full + " full trees "
254 // + "and one partial tree of size " + partial);
255 for (int i = 0; i < full; i++) {
256 trees[where++] = makeTree(treeHeight);
257 if (where == trees.length) where = 0;
258 }
259 while (partial > INSIGNIFICANT) {
260 int h = bytesToHeight(partial);
261 TreeNode newTree = makeTree(h);
262 replaceTree(trees[where++], newTree);
263 if (where == trees.length) where = 0;
264 partial = partial - heightToBytes(h);
265 }
266 }
267
268 // Interchanges two randomly selected subtrees (of same size and depth).
269
270 private static void oldGenSwapSubtrees() {
271 // Randomly pick:
272 // * two tree indices
273 // * A depth
274 // * A path to that depth.
275 int index1 = rnd.nextInt(trees.length);
276 int index2 = rnd.nextInt(trees.length);
277 int depth = rnd.nextInt(treeHeight);
278 int path = rnd.nextInt();
279 TreeNode tn1 = trees[index1];
280 TreeNode tn2 = trees[index2];
281 for (int i = 0; i < depth; i++) {
282 if ((path & 1) == 0) {
283 tn1 = tn1.left;
284 tn2 = tn2.left;
285 } else {
286 tn1 = tn1.right;
287 tn2 = tn2.right;
288 }
289 path >>= 1;
290 }
291 TreeNode tmp;
292 if ((path & 1) == 0) {
293 tmp = tn1.left;
294 tn1.left = tn2.left;
295 tn2.left = tmp;
296 } else {
297 tmp = tn1.right;
298 tn1.right = tn2.right;
299 tn2.right = tmp;
300 }
301 actuallyMut += 2;
302 }
303
304 // Update "n" old-generation pointers.
305
306 private static void oldGenMut(long n) {
307 for (int i = 0; i < n/2; i++) {
308 oldGenSwapSubtrees();
309 }
310 }
311
312 // Does the amount of mutator work appropriate for n bytes of young-gen
313 // garbage allocation.
314
315 private static void doMutWork(long n) {
316 int sum = 0;
317 long limit = workUnits*n/10;
318 for (long k = 0; k < limit; k++) sum++;
319 // We don't want dead code elimination to eliminate the loop above.
320 mutatorSum = mutatorSum + sum;
321 }
322
323 // Allocate n bytes of young-gen garbage, in units of "nwords"
324 // words.
325
326 private static void doYoungGenAlloc(long n, int nwords) {
327 final int nbytes = nwords*BYTES_PER_WORD;
328 int allocated = 0;
329 while (allocated < n) {
330 aexport = new int[nwords];
331 /* System.err.println("Step"); */
332 allocated += nbytes;
333 }
334 youngBytes = youngBytes + allocated;
335 }
336
337 // Allocate "n" bytes of young-gen data; and do the
338 // corresponding amount of old-gen allocation and pointer
339 // mutation.
340
341 // oldGenAlloc may perform some mutations, so this code
342 // takes those mutations into account.
343
344 private static void doStep(long n) {
345 long mutations = actuallyMut;
346
347 doYoungGenAlloc(n, WORDS_DEAD);
348 doMutWork(n);
349 oldGenAlloc(n / promoteRate);
350 oldGenMut(Math.max(0L, (mutations + ptrMutRate) - actuallyMut));
351 }
352
353 public static void main(String[] args) {
354 if (args.length != 5) {
355 System.err.println(msg1);
356 System.err.println(msg2);
357 System.err.println(msg3);
358 System.err.println(msg4);
359 System.err.println(msg5);
360 System.err.println(msg6);
361 return;
362 }
363
364 size = Integer.parseInt(args[0]);
365 workUnits = Integer.parseInt(args[1]);
366 promoteRate = Integer.parseInt(args[2]);
367 ptrMutRate = Integer.parseInt(args[3]);
368 steps = Integer.parseInt(args[4]);
369
370 System.out.println(size + " megabytes of live storage");
371 System.out.println(workUnits + " work units per step");
372 System.out.println("promotion ratio is 1:" + promoteRate);
373 System.out.println("pointer mutation rate is " + ptrMutRate);
374 System.out.println(steps + " steps");
375
376 init();
377 // checkTrees();
378 youngBytes = 0;
379 nodes = 0;
380
381 System.err.println("Initialization complete...");
382
383 long start = System.currentTimeMillis();
384
385 for (int step = 0; step < steps; step++) {
386 doStep(MEG);
387 }
388
389 long end = System.currentTimeMillis();
390 float secs = ((float)(end-start))/1000.0F;
391
392 // checkTrees();
393
394 NumberFormat nf = NumberFormat.getInstance();
395 nf.setMaximumFractionDigits(1);
396 System.out.println("\nTook " + nf.format(secs) + " sec in steady state.");
397 nf.setMaximumFractionDigits(2);
398 System.out.println("Allocated " + steps + " Mb of young gen garbage"
399 + " (= " + nf.format(((float)steps)/secs) +
400 " Mb/sec)");
401 System.out.println(" (actually allocated " +
402 nf.format(((float) youngBytes)/MEG) + " megabytes)");
403 float promoted = ((float)steps) / (float)promoteRate;
404 System.out.println("Promoted " + promoted +
405 " Mb (= " + nf.format(promoted/secs) + " Mb/sec)");
406 System.out.println(" (actually promoted " +
407 nf.format(((float) (nodes * BYTES_PER_NODE))/MEG) +
408 " megabytes)");
409 if (ptrMutRate != 0) {
410 System.out.println("Mutated " + actuallyMut +
411 " pointers (= " +
412 nf.format(actuallyMut/secs) + " ptrs/sec)");
413
414 }
415 // This output serves mainly to discourage optimization.
416 System.out.println("Checksum = " + (mutatorSum + aexport.length));
417
418 }
419 }