TestObjectAlignment.java

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package gc;

/**
 * @test TestObjectAlignment
 * @bug 8021823
 * @summary G1: Concurrent marking crashes with -XX:ObjectAlignmentInBytes>=32 in 64bit VMs
 * @library /test/lib
 * @modules java.base/jdk.internal.misc
 * @run main/othervm gc.TestObjectAlignment -Xmx20M -XX:+ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=8
 * @run main/othervm gc.TestObjectAlignment -Xmx20M -XX:+ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=16
 * @run main/othervm gc.TestObjectAlignment -Xmx20M -XX:+ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=32
 * @run main/othervm gc.TestObjectAlignment -Xmx20M -XX:+ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=64
 * @run main/othervm gc.TestObjectAlignment -Xmx20M -XX:+ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=128
 * @run main/othervm gc.TestObjectAlignment -Xmx20M -XX:+ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=256
 * @run main/othervm gc.TestObjectAlignment -Xmx20M -XX:-ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=8
 * @run main/othervm gc.TestObjectAlignment -Xmx20M -XX:-ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=16
 * @run main/othervm gc.TestObjectAlignment -Xmx20M -XX:-ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=32
 * @run main/othervm gc.TestObjectAlignment -Xmx20M -XX:-ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=64
 * @run main/othervm gc.TestObjectAlignment -Xmx20M -XX:-ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=128
 * @run main/othervm gc.TestObjectAlignment -Xmx20M -XX:-ExplicitGCInvokesConcurrent -XX:+IgnoreUnrecognizedVMOptions -XX:ObjectAlignmentInBytes=256
 */

public class TestObjectAlignment {

  public static byte[] garbage;

  private static boolean runsOn32bit() {
    return System.getProperty("sun.arch.data.model").equals("32");
  }

  public static void main(String[] args) throws Exception {
    if (runsOn32bit()) {
      // 32 bit VMs do not allow setting ObjectAlignmentInBytes, so there is nothing to test. We still get called.
      return;
    }
    for (int i = 0; i < 10; i++) {
      garbage = new byte[1000];
      System.gc();
    }
  }
}