test/hotspot/jtreg/gc/epsilon/TestElasticTLABDecay.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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/**
 * @test TestElasticTLABDecay
 * @key gc
 * @requires vm.gc.Epsilon & !vm.graal.enabled & os.maxMemory > 1G
 * @summary Epsilon is able to work with/without elastic TLABs
 *
 * @run main/othervm -Xmx1g -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC -XX:+EpsilonElasticTLAB -XX:-EpsilonElasticTLABDecay                               TestElasticTLABDecay
 * @run main/othervm -Xmx1g -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC -XX:+EpsilonElasticTLAB -XX:+EpsilonElasticTLABDecay -XX:EpsilonTLABDecayTime=1    TestElasticTLABDecay
 * @run main/othervm -Xmx1g -XX:+UnlockExperimentalVMOptions -XX:+UseEpsilonGC -XX:+EpsilonElasticTLAB -XX:+EpsilonElasticTLABDecay -XX:EpsilonTLABDecayTime=100  TestElasticTLABDecay
 */

import java.util.Random;

public class TestElasticTLABDecay {

  static long SEED = Long.getLong("seed", System.nanoTime());
  static int COUNT = Integer.getInteger("count", 3000); // ~500 MB allocation

  static byte[][] arr;

  public static void main(String[] args) throws Exception {
    Random r = new Random(SEED);

    arr = new byte[COUNT * 100][];
    for (int c = 0; c < COUNT; c++) {
      arr[c] = new byte[c * 100];
      for (int v = 0; v < c; v++) {
        arr[c][v] = (byte)(r.nextInt(255) & 0xFF);
      }
      Thread.sleep(5);
    }

    r = new Random(SEED);
    for (int c = 0; c < COUNT; c++) {
      byte[] b = arr[c];
      if (b.length != (c * 100)) {
        throw new IllegalStateException("Failure: length = " + b.length + ", need = " + (c*100));
      }
      for (int v = 0; v < c; v++) {
        byte actual = b[v];
        byte expected = (byte)(r.nextInt(255) & 0xFF);
        if (actual != expected) {
          throw new IllegalStateException("Failure: expected = " + expected + ", actual = " + actual);
        }
      }
    }
  }
}