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  1. ZooKeeper
  2. ZOOKEEPER-2790

Should we consider using `LongAdder` instead of `AtomicLong`

    Details

    • Type: Improvement
    • Status: Open
    • Priority: Major
    • Resolution: Unresolved
    • Affects Version/s: 3.5.3
    • Fix Version/s: 4.0.0
    • Component/s: server
    • Labels:
      None

      Description

      ```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 -Xmn256M -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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          Benedict Jin

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            • Assignee:
              Unassigned
              Reporter:
              benedict jin Benedict Jin
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              Dates

              • Created:
                Updated: