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Posted to dev@druid.apache.org by GitBox <gi...@apache.org> on 2018/07/11 00:57:42 UTC
[GitHub] asdf2014 commented on a change in pull request #5913: Move Caching
Cluster Client to java streams and allow parallel intermediate merges
asdf2014 commented on a change in pull request #5913: Move Caching Cluster Client to java streams and allow parallel intermediate merges
URL: https://github.com/apache/incubator-druid/pull/5913#discussion_r201538838
##########
File path: java-util/src/main/java/io/druid/java/util/common/concurrent/Execs.java
##########
@@ -147,4 +151,29 @@ public void rejectedExecution(Runnable r, ThreadPoolExecutor executor)
}
);
}
+
+ private static final AtomicLong fjpWorkerThreadCount = new AtomicLong(0L);
Review comment:
Using `LongAdder` will be better than `AtomicLong`. There is a source-level analysis in my personal blog, if you are interested, you can take a look.
Tips: [https://yuzhouwan.com/posts/31915#LongAdder](https://yuzhouwan.com/posts/31915#LongAdder)
```java
// -Xmx512M -Xms512M -Xmn256M -XX:+AlwaysPreTouch -ea
@Test
public void pressureLongAdder() throws Exception {
final LongAdder longAdder = new LongAdder();
ExecutorService executorService = Executors.newCachedThreadPool();
long startTime = System.currentTimeMillis();
for (int i = 0; i < 100; i++) {
executorService.submit(new Thread(() -> {
for (int j = 0; j < 1000_0000; j++) {
longAdder.increment();
}
System.out.print(String.format("%s %s \t", Thread.currentThread().getId(), longAdder.longValue()));
/*
14 19607585 12 36445036 20 38985288 38 76821270 70 117094732 18 127252576
22 137043349 26 153411172 30 164051380 34 165971155 102 192241678 134 201104979
158 232657818 46 279030056 174 288502545 94 347965290 198 348060553 118 348087414
36 353092712 28 357762215 44 365464475 126 379518198 54 379623515 182 380077075
142 385263911 78 389013887 62 389085727 110 389122678 86 389920423 166 393535019
150 396382512 190 403100499 32 403161217 208 403197689 206 406065520 16 410725026
24 415347205 40 415379997 48 415733397 104 418507295 192 423244160 176 455793362
168 458311865 160 463028656 136 496375440 72 541243645 186 561877000 170 575352229
162 584152392 154 604552121 138 614092854 64 638151890 114 668705836 58 669235250
188 699213410 156 729222401 124 754336889 100 784326386 76 813479501 120 827569944
66 830236567 98 832153503 112 841408676 204 849520891 210 852391130 202 864804732
172 875603834 194 877222893 200 881090909 88 882809513 80 882846368 56 887174571
178 889682247 140 901357028 146 902169049 184 904540678 152 915608988 130 917896629
116 924616135 144 927674541 122 930399321 128 939791111 106 942656234 84 950848174
96 951904067 90 954910184 74 964338213 196 966487766 82 968307139 52 975854400
180 977385398 164 978882525 50 980896807 148 988292352 132 989090669 108 996891232
92 996921398 42 996938988 68 996953941 60 1000000000
*/
}));
}
executorService.shutdown();
while (!executorService.isTerminated()) {
Thread.sleep(1);
}
long endTime = System.currentTimeMillis();
System.out.println("\n" + (endTime - startTime)); // 3275 ms
}
// -Xmx512M -Xms512M -Xmn128M -XX:+AlwaysPreTouch -ea
@Test
public void pressureAtomicLong() throws Exception {
final AtomicLong atomicLong = new AtomicLong();
ExecutorService executorService = Executors.newCachedThreadPool();
long startTime = System.currentTimeMillis();
for (int i = 0; i < 100; i++) {
executorService.submit(new Thread(() -> {
for (int j = 0; j < 1000_0000; j++) {
atomicLong.getAndIncrement();
}
System.out.print(String.format("%s %s \t", Thread.currentThread().getId(), atomicLong.longValue()));
/*
12 390000000 28 390000000 44 390000000 20 390000000 26 390000000 18 390000000
80 390000000 56 390000000 96 390000000 24 390000000 88 390000000 72 390000000
22 390000000 118 390000000 54 390000000 142 390000000 70 390000000 86 390000000
182 390000000 110 390000000 62 390000000 78 390000000 102 390000000 158 390000000
150 390000000 46 390000000 38 390000000 126 390000000 94 390000000 134 390000000
14 390000000 48 390000000 40 390000000 32 390000000 34 390000000 64 390000000
42 390000000 36 390000000 16 390000000 180 416396554 204 419908287 196 425536497
92 732203658 30 733835560 202 733835559 210 733873571 146 733878564 186 733883527
170 733888686 76 733892691 84 733888815 148 733901560 162 733907032 172 733908079
52 733913280 116 733918421 124 733906868 164 733920945 132 733891348 68 733923672
108 733924928 156 733926091 60 733921998 140 733927257 188 733928891 154 733871822
194 733830477 178 733872527 100 733830322 106 748251688 144 1000000000 98 1000000000
58 1000000000 90 1000000000 130 1000000000 138 1000000000 114 1000000000 104 1000000000
168 1000000000 200 1000000000 184 1000000000 160 1000000000 174 1000000000 112 1000000000
190 1000000000 198 1000000000 82 1000000000 206 1000000000 166 1000000000 176 1000000000
136 1000000000 208 1000000000 74 1000000000 122 1000000000 152 1000000000 192 1000000000
120 1000000000 128 1000000000 66 1000000000 50 1000000000
*/
}));
}
executorService.shutdown();
while (!executorService.isTerminated()) {
Thread.sleep(1);
}
long endTime = System.currentTimeMillis();
System.out.println("\n" + (endTime - startTime)); // 19409 ms
}
```
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