Java ScheduledExecutorService ПЛОХАЯ Точность

Привет, я написал простую программу для проверки точности функции ScduledExecutorService.schedule().

Тест устанавливает задержку и проверяет эффективное расстояние между требуемой задержкой и эффективным результатом.

Тест проводился на машине i7 под управлением Linux 3.8 x86_64 с OpenJDK 1.7 и Oracle JDK 1.7.

Результат теста действительно плохой, вот список, показывающий среднюю разницу между предполагаемой и эффективной задержкой:

Легенда:

Сон (мс): необходимая задержка в миллисекундах.
deltaAVG(ms): средняя разница между требуемой и эффективной задержкой, полученная в миллисекундах.
deltaAVG_PERC: требуемый/эффективный процент ошибок.
дельта MIN/MAX: минимальная/максимальная разница между полученной требуемой и эффективной задержкой.

Sleep(ms): 0.010 deltaAVG(ms): 0.029 deltaAVG_PERC: 0289.6 % delta MIN/MAX (ms): 0.029/0.029
Sleep(ms): 0.020 deltaAVG(ms): 0.061 deltaAVG_PERC: 0299.3 % delta MIN/MAX (ms): 0.006/4.578
Sleep(ms): 0.030 deltaAVG(ms): 0.066 deltaAVG_PERC: 0221.1 % delta MIN/MAX (ms): 0.009/1.639
Sleep(ms): 0.040 deltaAVG(ms): 0.066 deltaAVG_PERC: 0165.3 % delta MIN/MAX (ms): 0.010/0.445
Sleep(ms): 0.050 deltaAVG(ms): 0.069 deltaAVG_PERC: 0138.0 % delta MIN/MAX (ms): 0.006/0.370
Sleep(ms): 0.060 deltaAVG(ms): 0.067 deltaAVG_PERC: 0111.8 % delta MIN/MAX (ms): 0.052/0.700
Sleep(ms): 0.070 deltaAVG(ms): 0.067 deltaAVG_PERC: 0096.0 % delta MIN/MAX (ms): 0.053/5.597
Sleep(ms): 0.080 deltaAVG(ms): 0.067 deltaAVG_PERC: 0083.6 % delta MIN/MAX (ms): 0.054/1.978
Sleep(ms): 0.090 deltaAVG(ms): 0.065 deltaAVG_PERC: 0072.8 % delta MIN/MAX (ms): 0.034/1.548
Sleep(ms): 0.100 deltaAVG(ms): 0.066 deltaAVG_PERC: 0066.3 % delta MIN/MAX (ms): 0.026/1.969
Sleep(ms): 0.110 deltaAVG(ms): 0.065 deltaAVG_PERC: 0058.7 % delta MIN/MAX (ms): 0.036/1.075
Sleep(ms): 0.120 deltaAVG(ms): 0.064 deltaAVG_PERC: 0053.5 % delta MIN/MAX (ms): 0.012/0.454
Sleep(ms): 0.130 deltaAVG(ms): 0.067 deltaAVG_PERC: 0051.6 % delta MIN/MAX (ms): 0.038/1.523
Sleep(ms): 0.140 deltaAVG(ms): 0.066 deltaAVG_PERC: 0047.0 % delta MIN/MAX (ms): 0.038/0.544
Sleep(ms): 0.150 deltaAVG(ms): 0.066 deltaAVG_PERC: 0044.0 % delta MIN/MAX (ms): 0.031/0.498
Sleep(ms): 0.160 deltaAVG(ms): 0.065 deltaAVG_PERC: 0040.4 % delta MIN/MAX (ms): 0.022/0.432
Sleep(ms): 0.170 deltaAVG(ms): 0.067 deltaAVG_PERC: 0039.6 % delta MIN/MAX (ms): 0.031/0.229
Sleep(ms): 0.180 deltaAVG(ms): 0.071 deltaAVG_PERC: 0039.3 % delta MIN/MAX (ms): 0.046/0.291
Sleep(ms): 0.190 deltaAVG(ms): 0.074 deltaAVG_PERC: 0039.1 % delta MIN/MAX (ms): 0.042/1.069
Sleep(ms): 0.200 deltaAVG(ms): 0.071 deltaAVG_PERC: 0035.5 % delta MIN/MAX (ms): 0.031/0.293
Sleep(ms): 0.210 deltaAVG(ms): 0.072 deltaAVG_PERC: 0034.3 % delta MIN/MAX (ms): 0.028/1.058
Sleep(ms): 0.220 deltaAVG(ms): 0.075 deltaAVG_PERC: 0034.0 % delta MIN/MAX (ms): 0.055/1.879
Sleep(ms): 0.230 deltaAVG(ms): 0.075 deltaAVG_PERC: 0032.5 % delta MIN/MAX (ms): 0.040/0.514
Sleep(ms): 0.240 deltaAVG(ms): 0.075 deltaAVG_PERC: 0031.4 % delta MIN/MAX (ms): 0.055/1.715
Sleep(ms): 0.250 deltaAVG(ms): 0.075 deltaAVG_PERC: 0030.2 % delta MIN/MAX (ms): 0.044/1.025
Sleep(ms): 0.260 deltaAVG(ms): 0.076 deltaAVG_PERC: 0029.2 % delta MIN/MAX (ms): 0.038/1.561
Sleep(ms): 0.270 deltaAVG(ms): 0.076 deltaAVG_PERC: 0028.1 % delta MIN/MAX (ms): 0.050/0.697
Sleep(ms): 0.280 deltaAVG(ms): 0.075 deltaAVG_PERC: 0026.8 % delta MIN/MAX (ms): 0.039/0.996
Sleep(ms): 0.290 deltaAVG(ms): 0.076 deltaAVG_PERC: 0026.3 % delta MIN/MAX (ms): 0.032/0.475
Sleep(ms): 0.300 deltaAVG(ms): 0.077 deltaAVG_PERC: 0025.6 % delta MIN/MAX (ms): 0.055/2.136
Sleep(ms): 0.310 deltaAVG(ms): 0.077 deltaAVG_PERC: 0024.9 % delta MIN/MAX (ms): 0.042/0.373
Sleep(ms): 0.320 deltaAVG(ms): 0.079 deltaAVG_PERC: 0024.6 % delta MIN/MAX (ms): 0.036/2.622
Sleep(ms): 0.330 deltaAVG(ms): 0.080 deltaAVG_PERC: 0024.3 % delta MIN/MAX (ms): 0.038/1.367
Sleep(ms): 0.340 deltaAVG(ms): 0.080 deltaAVG_PERC: 0023.5 % delta MIN/MAX (ms): 0.028/0.308
Sleep(ms): 0.350 deltaAVG(ms): 0.079 deltaAVG_PERC: 0022.7 % delta MIN/MAX (ms): 0.055/1.885
Sleep(ms): 0.360 deltaAVG(ms): 0.076 deltaAVG_PERC: 0021.1 % delta MIN/MAX (ms): 0.053/0.403
Sleep(ms): 0.370 deltaAVG(ms): 0.079 deltaAVG_PERC: 0021.3 % delta MIN/MAX (ms): 0.056/0.390
Sleep(ms): 0.380 deltaAVG(ms): 0.079 deltaAVG_PERC: 0020.9 % delta MIN/MAX (ms): 0.055/3.777
Sleep(ms): 0.390 deltaAVG(ms): 0.081 deltaAVG_PERC: 0020.9 % delta MIN/MAX (ms): 0.058/0.320
Sleep(ms): 0.400 deltaAVG(ms): 0.080 deltaAVG_PERC: 0019.9 % delta MIN/MAX (ms): 0.056/0.203
Sleep(ms): 0.410 deltaAVG(ms): 0.082 deltaAVG_PERC: 0019.9 % delta MIN/MAX (ms): 0.051/0.562
Sleep(ms): 0.420 deltaAVG(ms): 0.082 deltaAVG_PERC: 0019.6 % delta MIN/MAX (ms): 0.056/0.913
Sleep(ms): 0.430 deltaAVG(ms): 0.080 deltaAVG_PERC: 0018.6 % delta MIN/MAX (ms): 0.053/0.938
Sleep(ms): 0.440 deltaAVG(ms): 0.085 deltaAVG_PERC: 0019.4 % delta MIN/MAX (ms): 0.055/0.582
Sleep(ms): 0.450 deltaAVG(ms): 0.086 deltaAVG_PERC: 0019.1 % delta MIN/MAX (ms): 0.041/0.179
Sleep(ms): 0.460 deltaAVG(ms): 0.083 deltaAVG_PERC: 0018.0 % delta MIN/MAX (ms): 0.032/0.235
Sleep(ms): 0.470 deltaAVG(ms): 0.088 deltaAVG_PERC: 0018.6 % delta MIN/MAX (ms): 0.042/0.581
Sleep(ms): 0.480 deltaAVG(ms): 0.088 deltaAVG_PERC: 0018.3 % delta MIN/MAX (ms): 0.040/0.477
Sleep(ms): 0.490 deltaAVG(ms): 0.086 deltaAVG_PERC: 0017.5 % delta MIN/MAX (ms): 0.032/0.931
Sleep(ms): 0.500 deltaAVG(ms): 0.088 deltaAVG_PERC: 0017.5 % delta MIN/MAX (ms): 0.055/0.521
Sleep(ms): 0.510 deltaAVG(ms): 0.081 deltaAVG_PERC: 0016.0 % delta MIN/MAX (ms): 0.056/0.225
Sleep(ms): 0.520 deltaAVG(ms): 0.088 deltaAVG_PERC: 0016.9 % delta MIN/MAX (ms): 0.055/0.344
Sleep(ms): 0.530 deltaAVG(ms): 0.085 deltaAVG_PERC: 0016.0 % delta MIN/MAX (ms): 0.035/0.819
Sleep(ms): 0.540 deltaAVG(ms): 0.084 deltaAVG_PERC: 0015.6 % delta MIN/MAX (ms): 0.026/0.961
Sleep(ms): 0.550 deltaAVG(ms): 0.093 deltaAVG_PERC: 0016.9 % delta MIN/MAX (ms): 0.058/0.570
Sleep(ms): 0.560 deltaAVG(ms): 0.085 deltaAVG_PERC: 0015.3 % delta MIN/MAX (ms): 0.033/0.176
Sleep(ms): 0.570 deltaAVG(ms): 0.090 deltaAVG_PERC: 0015.8 % delta MIN/MAX (ms): 0.043/0.289
Sleep(ms): 0.580 deltaAVG(ms): 0.087 deltaAVG_PERC: 0014.9 % delta MIN/MAX (ms): 0.041/0.258
Sleep(ms): 0.590 deltaAVG(ms): 0.082 deltaAVG_PERC: 0013.9 % delta MIN/MAX (ms): 0.057/0.352
Sleep(ms): 0.600 deltaAVG(ms): 0.083 deltaAVG_PERC: 0013.9 % delta MIN/MAX (ms): 0.060/0.393
Sleep(ms): 0.610 deltaAVG(ms): 0.084 deltaAVG_PERC: 0013.8 % delta MIN/MAX (ms): 0.059/0.177
Sleep(ms): 0.620 deltaAVG(ms): 0.095 deltaAVG_PERC: 0015.3 % delta MIN/MAX (ms): 0.041/0.273
Sleep(ms): 0.630 deltaAVG(ms): 0.080 deltaAVG_PERC: 0012.6 % delta MIN/MAX (ms): 0.059/0.253
Sleep(ms): 0.640 deltaAVG(ms): 0.085 deltaAVG_PERC: 0013.3 % delta MIN/MAX (ms): 0.060/0.422
Sleep(ms): 0.650 deltaAVG(ms): 0.100 deltaAVG_PERC: 0015.4 % delta MIN/MAX (ms): 0.050/0.641
Sleep(ms): 0.660 deltaAVG(ms): 0.090 deltaAVG_PERC: 0013.7 % delta MIN/MAX (ms): 0.058/0.170
Sleep(ms): 0.670 deltaAVG(ms): 0.097 deltaAVG_PERC: 0014.5 % delta MIN/MAX (ms): 0.055/0.578
Sleep(ms): 0.680 deltaAVG(ms): 0.094 deltaAVG_PERC: 0013.8 % delta MIN/MAX (ms): 0.060/3.560
Sleep(ms): 0.690 deltaAVG(ms): 0.092 deltaAVG_PERC: 0013.3 % delta MIN/MAX (ms): 0.059/0.178
Sleep(ms): 0.700 deltaAVG(ms): 0.094 deltaAVG_PERC: 0013.4 % delta MIN/MAX (ms): 0.060/0.202
Sleep(ms): 0.710 deltaAVG(ms): 0.102 deltaAVG_PERC: 0014.3 % delta MIN/MAX (ms): 0.056/0.227
Sleep(ms): 0.720 deltaAVG(ms): 0.084 deltaAVG_PERC: 0011.7 % delta MIN/MAX (ms): 0.060/0.177
Sleep(ms): 0.730 deltaAVG(ms): 0.099 deltaAVG_PERC: 0013.5 % delta MIN/MAX (ms): 0.046/0.723
Sleep(ms): 0.740 deltaAVG(ms): 0.098 deltaAVG_PERC: 0013.2 % delta MIN/MAX (ms): 0.058/0.203
Sleep(ms): 0.750 deltaAVG(ms): 0.104 deltaAVG_PERC: 0013.9 % delta MIN/MAX (ms): 0.059/0.274
Sleep(ms): 0.760 deltaAVG(ms): 0.105 deltaAVG_PERC: 0013.8 % delta MIN/MAX (ms): 0.056/0.274
Sleep(ms): 0.770 deltaAVG(ms): 0.104 deltaAVG_PERC: 0013.5 % delta MIN/MAX (ms): 0.056/0.631
Sleep(ms): 0.780 deltaAVG(ms): 0.099 deltaAVG_PERC: 0012.7 % delta MIN/MAX (ms): 0.044/0.191
Sleep(ms): 0.790 deltaAVG(ms): 0.099 deltaAVG_PERC: 0012.5 % delta MIN/MAX (ms): 0.041/0.167
Sleep(ms): 0.800 deltaAVG(ms): 0.104 deltaAVG_PERC: 0013.0 % delta MIN/MAX (ms): 0.044/0.223
Sleep(ms): 0.810 deltaAVG(ms): 0.095 deltaAVG_PERC: 0011.7 % delta MIN/MAX (ms): 0.060/0.761
Sleep(ms): 0.820 deltaAVG(ms): 0.101 deltaAVG_PERC: 0012.3 % delta MIN/MAX (ms): 0.058/0.231
Sleep(ms): 0.830 deltaAVG(ms): 0.102 deltaAVG_PERC: 0012.3 % delta MIN/MAX (ms): 0.060/0.552
Sleep(ms): 0.840 deltaAVG(ms): 0.106 deltaAVG_PERC: 0012.6 % delta MIN/MAX (ms): 0.060/0.517
Sleep(ms): 0.850 deltaAVG(ms): 0.109 deltaAVG_PERC: 0012.9 % delta MIN/MAX (ms): 0.061/0.204
Sleep(ms): 0.860 deltaAVG(ms): 0.107 deltaAVG_PERC: 0012.5 % delta MIN/MAX (ms): 0.062/0.532
Sleep(ms): 0.870 deltaAVG(ms): 0.109 deltaAVG_PERC: 0012.5 % delta MIN/MAX (ms): 0.061/0.266
Sleep(ms): 0.880 deltaAVG(ms): 0.108 deltaAVG_PERC: 0012.3 % delta MIN/MAX (ms): 0.057/0.753
Sleep(ms): 0.890 deltaAVG(ms): 0.108 deltaAVG_PERC: 0012.2 % delta MIN/MAX (ms): 0.060/0.553
Sleep(ms): 0.900 deltaAVG(ms): 0.108 deltaAVG_PERC: 0011.9 % delta MIN/MAX (ms): 0.056/0.369
Sleep(ms): 0.910 deltaAVG(ms): 0.106 deltaAVG_PERC: 0011.6 % delta MIN/MAX (ms): 0.057/0.213
Sleep(ms): 0.920 deltaAVG(ms): 0.107 deltaAVG_PERC: 0011.6 % delta MIN/MAX (ms): 0.057/0.185
Sleep(ms): 0.930 deltaAVG(ms): 0.107 deltaAVG_PERC: 0011.5 % delta MIN/MAX (ms): 0.044/0.842
Sleep(ms): 0.940 deltaAVG(ms): 0.111 deltaAVG_PERC: 0011.8 % delta MIN/MAX (ms): 0.064/0.395
Sleep(ms): 0.950 deltaAVG(ms): 0.108 deltaAVG_PERC: 0011.4 % delta MIN/MAX (ms): 0.061/0.207
Sleep(ms): 0.960 deltaAVG(ms): 0.110 deltaAVG_PERC: 0011.5 % delta MIN/MAX (ms): 0.042/0.215
Sleep(ms): 0.970 deltaAVG(ms): 0.107 deltaAVG_PERC: 0011.0 % delta MIN/MAX (ms): 0.049/0.646
Sleep(ms): 0.980 deltaAVG(ms): 0.110 deltaAVG_PERC: 0011.2 % delta MIN/MAX (ms): 0.059/0.317
Sleep(ms): 0.990 deltaAVG(ms): 0.109 deltaAVG_PERC: 0011.0 % delta MIN/MAX (ms): 0.061/0.205
Sleep(ms): 1.000 deltaAVG(ms): 0.103 deltaAVG_PERC: 0010.3 % delta MIN/MAX (ms): 0.052/0.283
Sleep(ms): 1.010 deltaAVG(ms): 0.109 deltaAVG_PERC: 0010.8 % delta MIN/MAX (ms): 0.058/0.295
Sleep(ms): 1.020 deltaAVG(ms): 0.107 deltaAVG_PERC: 0010.5 % delta MIN/MAX (ms): 0.063/0.562
Sleep(ms): 1.030 deltaAVG(ms): 0.105 deltaAVG_PERC: 0010.2 % delta MIN/MAX (ms): 0.060/0.256
Sleep(ms): 1.040 deltaAVG(ms): 0.110 deltaAVG_PERC: 0010.6 % delta MIN/MAX (ms): 0.059/0.231
Sleep(ms): 1.050 deltaAVG(ms): 0.110 deltaAVG_PERC: 0010.5 % delta MIN/MAX (ms): 0.059/0.570
Sleep(ms): 1.060 deltaAVG(ms): 0.109 deltaAVG_PERC: 0010.2 % delta MIN/MAX (ms): 0.059/0.210
Sleep(ms): 1.070 deltaAVG(ms): 0.110 deltaAVG_PERC: 0010.3 % delta MIN/MAX (ms): 0.035/0.460
Sleep(ms): 1.080 deltaAVG(ms): 0.110 deltaAVG_PERC: 0010.2 % delta MIN/MAX (ms): 0.062/0.189
Sleep(ms): 1.090 deltaAVG(ms): 0.110 deltaAVG_PERC: 0010.1 % delta MIN/MAX (ms): 0.058/0.228
Sleep(ms): 1.100 deltaAVG(ms): 0.111 deltaAVG_PERC: 0010.0 % delta MIN/MAX (ms): 0.061/0.513
Sleep(ms): 1.110 deltaAVG(ms): 0.110 deltaAVG_PERC: 0009.9 % delta MIN/MAX (ms): 0.052/0.200
Sleep(ms): 1.120 deltaAVG(ms): 0.110 deltaAVG_PERC: 0009.9 % delta MIN/MAX (ms): 0.048/0.248
Sleep(ms): 1.130 deltaAVG(ms): 0.108 deltaAVG_PERC: 0009.6 % delta MIN/MAX (ms): 0.061/0.570
Sleep(ms): 1.140 deltaAVG(ms): 0.111 deltaAVG_PERC: 0009.7 % delta MIN/MAX (ms): 0.065/0.184
Sleep(ms): 1.150 deltaAVG(ms): 0.112 deltaAVG_PERC: 0009.7 % delta MIN/MAX (ms): 0.063/0.449
Sleep(ms): 1.160 deltaAVG(ms): 0.109 deltaAVG_PERC: 0009.4 % delta MIN/MAX (ms): 0.049/0.298
Sleep(ms): 1.170 deltaAVG(ms): 0.107 deltaAVG_PERC: 0009.1 % delta MIN/MAX (ms): 0.059/0.212
Sleep(ms): 1.180 deltaAVG(ms): 0.107 deltaAVG_PERC: 0009.1 % delta MIN/MAX (ms): 0.060/0.224
Sleep(ms): 1.190 deltaAVG(ms): 0.114 deltaAVG_PERC: 0009.6 % delta MIN/MAX (ms): 0.061/0.217
Sleep(ms): 1.200 deltaAVG(ms): 0.109 deltaAVG_PERC: 0009.1 % delta MIN/MAX (ms): 0.058/0.231
Sleep(ms): 1.210 deltaAVG(ms): 0.115 deltaAVG_PERC: 0009.5 % delta MIN/MAX (ms): 0.061/0.237
Sleep(ms): 1.220 deltaAVG(ms): 0.108 deltaAVG_PERC: 0008.8 % delta MIN/MAX (ms): 0.063/0.207
Sleep(ms): 1.230 deltaAVG(ms): 0.107 deltaAVG_PERC: 0008.7 % delta MIN/MAX (ms): 0.059/0.355
Sleep(ms): 1.240 deltaAVG(ms): 0.113 deltaAVG_PERC: 0009.1 % delta MIN/MAX (ms): 0.059/0.197
Sleep(ms): 1.250 deltaAVG(ms): 0.114 deltaAVG_PERC: 0009.1 % delta MIN/MAX (ms): 0.059/0.235
Sleep(ms): 1.260 deltaAVG(ms): 0.113 deltaAVG_PERC: 0009.0 % delta MIN/MAX (ms): 0.061/0.219
Sleep(ms): 1.270 deltaAVG(ms): 0.113 deltaAVG_PERC: 0008.9 % delta MIN/MAX (ms): 0.060/0.284
Sleep(ms): 1.280 deltaAVG(ms): 0.112 deltaAVG_PERC: 0008.8 % delta MIN/MAX (ms): 0.060/0.222
Sleep(ms): 1.290 deltaAVG(ms): 0.114 deltaAVG_PERC: 0008.9 % delta MIN/MAX (ms): 0.063/0.182
Sleep(ms): 1.300 deltaAVG(ms): 0.112 deltaAVG_PERC: 0008.6 % delta MIN/MAX (ms): 0.058/0.209

Как вы можете видеть, средняя ошибка, называемая deltaAVG, увеличивается по сравнению с задержкой.

Как можно получить лучший результат при задержке? Я имею в виду, что частота ошибок 300% на 10 микросекундах на машине i7 - это слишком много.

вот код, который я использовал для тестирования:

package threadexecutor_perftest;

import java.text.DecimalFormat;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
import statistica.timedValuesAverage;

/**
 *
 * @author salvatore novelli salvatore.novelli  domain   gmail.com
 */
public class ThreadExecutor_PerfTest implements Runnable, ThreadFactory {

    private final ScheduledExecutorService executor;
    private long start;
    private long stop;
    private long delay_nano = 10000;
    private final int averageTimeLen_ms = 2000;
    private TimedValuesAverage<Double> deltaAVG = new TimedValuesAverage<>(averageTimeLen_ms);
    DecimalFormat int3 = new DecimalFormat("0.000");
    DecimalFormat int4 = new DecimalFormat("0000.0");

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        ThreadExecutor_PerfTest test = new ThreadExecutor_PerfTest();

        test.start();

    }

    public ThreadExecutor_PerfTest() {
        executor = Executors.newSingleThreadScheduledExecutor(this);

    }

    public boolean start() {
        executor.schedule(this, 0L, TimeUnit.NANOSECONDS);
        return true;
    }

    private long DBG_lastReport;

    @Override
    public void run() {

        stop = System.nanoTime();

        if (start > 0) {

            long deltaT = (stop - start) - delay_nano;
            deltaAVG.put((double) deltaT);

            //report status every averageTimeLen_ms
            if ((System.currentTimeMillis() - DBG_lastReport) > averageTimeLen_ms) {

                System.out.println("    Sleep(ms): " + int3.format(delay_nano / 1000000.0)
                        + " deltaAVG(ms): " + int3.format(deltaAVG.getAverage() / 1000000.0)
                        + " deltaAVG_PERC: " + int4.format((deltaAVG.getAverage() /     delay_nano) * 100)+" %"
                        + " delta MIN/MAX (ms): " +     int3.format(deltaAVG.getSmallestEver() /     1000000.0) + "/" + int3.format(deltaAVG.getGreatestEver() / 1000000.0));

                //increase delay by 10 micro seconds (1000 nano seconds)
                delay_nano += 10000;
                deltaAVG = new TimedValuesAverage<>(averageTimeLen_ms);
                DBG_lastReport = System.currentTimeMillis();
            }
        }

        start = System.nanoTime();
        executor.schedule(this, delay_nano, TimeUnit.NANOSECONDS);
    }

    @Override
    public Thread newThread(Runnable r) {
        Thread t = new Thread(r, "Exec-test");
        t.setPriority(Thread.MAX_PRIORITY);
        return t;
    }

}

java scheduledexecutorservice time-precision

snovelli 27.11.2013 источник

comment

Пожалуйста, проверьте эту ссылку. В двух словах, в большинстве случаев у вас не может быть точного исполнения за такое небольшое количество времени. Если вам это нужно, вы должны использовать какой-то нативный подход. - n1ckolas 27.11.2013

comment

Вы пробовали scheduleAtFixedRate или scheduleWithFixedDelay? Похоже, вы пытались (6 лет назад) добиться того, что предлагает scheduleWithFixedDelay из коробки и, возможно, с большей точностью. Я использую scheduleAtFixedRate с периодом 400 мкс, и ошибка не так уж велика: до 3% со случайными всплесками во время GC. - MeTTeO 22.02.2020

Ответы (2)

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Executors.newSingleThreadScheduledExecutor(this); использует ScheduledThreadPoolExecutor под капотом. В JavaDocs для этого класса указано:

Отложенные задачи выполняются не раньше, чем они будут включены, но без каких-либо гарантий в реальном времени о том, когда после их включения они начнутся. Задачи, запланированные на одно и то же время выполнения, включаются в порядке поступления (FIFO).

Как указал n1ckolas, у вас возникнут трудности с получением такой точности в чистой Java.

Однако есть некоторые вещи, которые вы можете попробовать, которые могут быть более точными, чем ScheduledThreadPoolExecutor, хотя их точность будет зависеть от ОС , оборудование и т.д.

Pace 27.11.2013

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В любом случае квант планировщика вашей ОС, вероятно, не превышает 10 мс, поэтому попытка полагаться на таймер на основе потоков в пользовательском пространстве будет бесполезной. См. этот ответ, который в основном говорит то же самое.

Лучше всего в Java-земле стрелять java.util.concurrent.locks.LockSupport и parkNanos() методами. Но ниже 10 мс вам все равно не повезет - из-за ОС, а не Java.

Если вы больше ничего не читаете, прочитайте это. Этот ответ правильный.

brettw 27.11.2013

Java ScheduledExecutorService ПЛОХАЯ Точность

Ответы (2)

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