АСУ ТП в облаке — быстрая разработка проектов

**Владимир Ситников** · 29.01.2016, 15:47

Сообщение от capzap

вот есть авторитетный замерщик ему можно верить

Опять перевираете.
Полностью звучит так: вот есть способ проверить.

Ну, давайте, я проверю. Вам от этого легче станет?
Вот если вы запустите нормальный jmh тест, а не то убожество с однократным запуском, то это уже другое дело. Может, глаза откроются.

Расчехляем jmh, и получаем, что скорость выполнения одна и та же.

Код:

import org.openjdk.jmh.annotations.Benchmark;
import org.openjdk.jmh.annotations.BenchmarkMode;
import org.openjdk.jmh.annotations.Fork;
import org.openjdk.jmh.annotations.Measurement;
import org.openjdk.jmh.annotations.Mode;
import org.openjdk.jmh.annotations.OutputTimeUnit;
import org.openjdk.jmh.annotations.Scope;
import org.openjdk.jmh.annotations.State;
import org.openjdk.jmh.annotations.Threads;
import org.openjdk.jmh.annotations.Warmup;
import org.openjdk.jmh.runner.Runner;
import org.openjdk.jmh.runner.RunnerException;
import org.openjdk.jmh.runner.options.Options;
import org.openjdk.jmh.runner.options.OptionsBuilder;

import java.util.concurrent.TimeUnit;

@Fork(value = 3, jvmArgsPrepend = {"-Xms2g", "-Xmx2g"})
@Measurement(iterations = 10, time = 1, timeUnit = TimeUnit.SECONDS)
@Warmup(iterations = 10, time = 1, timeUnit = TimeUnit.SECONDS)
@State(Scope.Thread)
@Threads(1)
@BenchmarkMode(Mode.AverageTime)
@OutputTimeUnit(TimeUnit.MILLISECONDS)
public class StringConcat {

  @Benchmark
  public String builder() {
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < 1e7; i++) {
      sb.append("Irbis");
    }
    return sb.toString();
  }

  @Benchmark
  public String buffer() {
    StringBuffer sb = new StringBuffer();
    for (int i = 0; i < 1e7; i++) {
      sb.append("Irbis");
    }
    return sb.toString();
  }

  public static void main(String[] args) throws RunnerException {
    Options opt = new OptionsBuilder()
        .include(StringConcat.class.getSimpleName())
        //.addProfiler(GCProfiler.class)
        .detectJvmArgs()
        .build();

    new Runner(opt).run();
  }

}

Код:

# JMH 1.11.2 (released 92 days ago, please consider updating!)
# VM version: JDK 1.8.0_60, VM 25.60-b23
# VM invoker: /Library/Java/JavaVirtualMachines/jdk1.8.0_60.jdk/Contents/Home/jre/bin/java
# VM options: -Xms2g -Xmx2g -Didea.launcher.port=7532 -Didea.launcher.bin.path=/Applications/IntelliJ IDEA 15.app/Contents/bin -Dfile.encoding=UTF-8
# Warmup: 10 iterations, 1 s each
# Measurement: 10 iterations, 1 s each
# Timeout: 10 min per iteration
# Threads: 1 thread, will synchronize iterations
# Benchmark mode: Average time, time/op
# Benchmark: org.postgresql.util.StringConcat.buffer

# Run progress: 0,00% complete, ETA 00:02:00
# Fork: 1 of 3
# Warmup Iteration   1: 504,478 ms/op
# Warmup Iteration   2: 167,282 ms/op
# Warmup Iteration   3: 156,712 ms/op
# Warmup Iteration   4: 142,019 ms/op
# Warmup Iteration   5: 130,716 ms/op
# Warmup Iteration   6: 132,175 ms/op
# Warmup Iteration   7: 130,494 ms/op
# Warmup Iteration   8: 128,751 ms/op
# Warmup Iteration   9: 128,376 ms/op
# Warmup Iteration  10: 135,927 ms/op
Iteration   1: 142,503 ms/op
Iteration   2: 126,427 ms/op
Iteration   3: 121,183 ms/op
Iteration   4: 123,705 ms/op
Iteration   5: 134,235 ms/op
Iteration   6: 122,471 ms/op
Iteration   7: 124,813 ms/op
Iteration   8: 127,109 ms/op
Iteration   9: 122,452 ms/op
Iteration  10: 128,862 ms/op

# Run progress: 16,67% complete, ETA 00:01:50
# Fork: 2 of 3
# Warmup Iteration   1: 290,340 ms/op
# Warmup Iteration   2: 133,337 ms/op
# Warmup Iteration   3: 123,226 ms/op
# Warmup Iteration   4: 131,857 ms/op
# Warmup Iteration   5: 128,725 ms/op
# Warmup Iteration   6: 129,772 ms/op
# Warmup Iteration   7: 123,170 ms/op
# Warmup Iteration   8: 122,863 ms/op
# Warmup Iteration   9: 129,920 ms/op
# Warmup Iteration  10: 120,862 ms/op
Iteration   1: 122,446 ms/op
Iteration   2: 124,428 ms/op
Iteration   3: 133,191 ms/op
Iteration   4: 119,475 ms/op
Iteration   5: 126,896 ms/op
Iteration   6: 123,963 ms/op
Iteration   7: 134,483 ms/op
Iteration   8: 133,446 ms/op
Iteration   9: 127,896 ms/op
Iteration  10: 125,156 ms/op

# Run progress: 33,33% complete, ETA 00:01:28
# Fork: 3 of 3
# Warmup Iteration   1: 285,805 ms/op
# Warmup Iteration   2: 130,223 ms/op
# Warmup Iteration   3: 122,691 ms/op
# Warmup Iteration   4: 132,281 ms/op
# Warmup Iteration   5: 130,149 ms/op
# Warmup Iteration   6: 129,617 ms/op
# Warmup Iteration   7: 125,146 ms/op
# Warmup Iteration   8: 125,089 ms/op
# Warmup Iteration   9: 133,226 ms/op
# Warmup Iteration  10: 125,234 ms/op
Iteration   1: 119,962 ms/op
Iteration   2: 126,932 ms/op
Iteration   3: 132,335 ms/op
Iteration   4: 131,525 ms/op
Iteration   5: 127,541 ms/op
Iteration   6: 121,408 ms/op
Iteration   7: 119,892 ms/op
Iteration   8: 139,716 ms/op
Iteration   9: 121,877 ms/op
Iteration  10: 125,758 ms/op


Result "buffer":
  127,070 ±(99.9%) 3,904 ms/op [Average]
  (min, avg, max) = (119,475, 127,070, 142,503), stdev = 5,844
  CI (99.9%): [123,165, 130,974] (assumes normal distribution)


# JMH 1.11.2 (released 92 days ago, please consider updating!)
# VM version: JDK 1.8.0_60, VM 25.60-b23
# VM invoker: /Library/Java/JavaVirtualMachines/jdk1.8.0_60.jdk/Contents/Home/jre/bin/java
# VM options: -Xms2g -Xmx2g -Didea.launcher.port=7532 -Didea.launcher.bin.path=/Applications/IntelliJ IDEA 15.app/Contents/bin -Dfile.encoding=UTF-8
# Warmup: 10 iterations, 1 s each
# Measurement: 10 iterations, 1 s each
# Timeout: 10 min per iteration
# Threads: 1 thread, will synchronize iterations
# Benchmark mode: Average time, time/op
# Benchmark: org.postgresql.util.StringConcat.builder

# Run progress: 50,00% complete, ETA 00:01:06
# Fork: 1 of 3
# Warmup Iteration   1: 177,462 ms/op
# Warmup Iteration   2: 127,427 ms/op
# Warmup Iteration   3: 116,823 ms/op
# Warmup Iteration   4: 128,042 ms/op
# Warmup Iteration   5: 126,923 ms/op
# Warmup Iteration   6: 123,174 ms/op
# Warmup Iteration   7: 125,599 ms/op
# Warmup Iteration   8: 127,271 ms/op
# Warmup Iteration   9: 128,333 ms/op
# Warmup Iteration  10: 114,842 ms/op
Iteration   1: 128,124 ms/op
Iteration   2: 117,573 ms/op
Iteration   3: 126,854 ms/op
Iteration   4: 127,813 ms/op
Iteration   5: 116,706 ms/op
Iteration   6: 120,092 ms/op
Iteration   7: 122,443 ms/op
Iteration   8: 124,191 ms/op
Iteration   9: 125,831 ms/op
Iteration  10: 121,483 ms/op

# Run progress: 66,67% complete, ETA 00:00:44
# Fork: 2 of 3
# Warmup Iteration   1: 175,898 ms/op
# Warmup Iteration   2: 129,208 ms/op
# Warmup Iteration   3: 125,624 ms/op
# Warmup Iteration   4: 117,651 ms/op
# Warmup Iteration   5: 129,693 ms/op
# Warmup Iteration   6: 122,625 ms/op
# Warmup Iteration   7: 117,697 ms/op
# Warmup Iteration   8: 118,748 ms/op
# Warmup Iteration   9: 129,949 ms/op
# Warmup Iteration  10: 129,812 ms/op
Iteration   1: 122,881 ms/op
Iteration   2: 120,961 ms/op
Iteration   3: 116,294 ms/op
Iteration   4: 129,627 ms/op
Iteration   5: 122,964 ms/op
Iteration   6: 117,850 ms/op
Iteration   7: 124,518 ms/op
Iteration   8: 169,902 ms/op
Iteration   9: 124,100 ms/op
Iteration  10: 124,082 ms/op

# Run progress: 83,33% complete, ETA 00:00:22
# Fork: 3 of 3
# Warmup Iteration   1: 178,994 ms/op
# Warmup Iteration   2: 129,012 ms/op
# Warmup Iteration   3: 133,074 ms/op
# Warmup Iteration   4: 123,572 ms/op
# Warmup Iteration   5: 137,259 ms/op
# Warmup Iteration   6: 125,592 ms/op
# Warmup Iteration   7: 125,917 ms/op
# Warmup Iteration   8: 125,565 ms/op
# Warmup Iteration   9: 134,758 ms/op
# Warmup Iteration  10: 123,280 ms/op
Iteration   1: 121,962 ms/op
Iteration   2: 121,457 ms/op
Iteration   3: 129,659 ms/op
Iteration   4: 136,555 ms/op
Iteration   5: 130,896 ms/op
Iteration   6: 136,405 ms/op
Iteration   7: 128,355 ms/op
Iteration   8: 138,604 ms/op
Iteration   9: 130,620 ms/op
Iteration  10: 126,581 ms/op


Result "builder":
  126,846 ±(99.9%) 6,624 ms/op [Average]
  (min, avg, max) = (116,294, 126,846, 169,902), stdev = 9,915
  CI (99.9%): [120,222, 133,470] (assumes normal distribution)

Код:

# Run complete. Total time: 00:02:12

Benchmark             Mode  Cnt    Score   Error  Units
StringConcat.buffer   avgt   30  127,070 ± 3,904  ms/op
StringConcat.builder  avgt   30  126,846 ± 6,624  ms/op

Т.е. различие в 0.2мс при том, что статистическая ошибка порядка 10мс.

Тема: АСУ ТП в облаке — быстрая разработка проектов

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