Package org.openjdk.jmh.infra

Class Blackhole

java.lang.Object
org.openjdk.jmh.infra.Blackhole
public final class Blackhole extends Object
Black Hole.

Black hole "consumes" the values, conceiving no information to JIT whether the value is actually used afterwards. This can save from the dead-code elimination of the computations resulting in the given values.

  • Field Details

    • b1

      public volatile byte b1

    • bool1

      public volatile boolean bool1

    • c1

      public volatile char c1

    • s1

      public volatile short s1

    • i1

      public volatile int i1

    • l1

      public volatile long l1

    • f1

      public volatile float f1

    • d1

      public volatile double d1

    • b2

      public byte b2

    • bool2

      public boolean bool2

    • c2

      public char c2

    • s2

      public short s2

    • i2

      public int i2

    • l2

      public long l2

    • f2

      public float f2

    • d2

      public double d2

    • obj1

      public volatile Object obj1

    • nullBait

      public volatile org.openjdk.jmh.infra.BlackholeL2 nullBait

    • tlr

      public int tlr

    • tlrMask

      public volatile int tlrMask

  • Constructor Details

    • Blackhole

      public Blackhole(String challengeResponse)

  • Method Details

    • evaporate

      public void evaporate(String challengeResponse)
      Make any consumed data begone. WARNING: This method should only be called by the infrastructure code, in clearly understood cases. Even though it is public, it is not supposed to be called by users.
      Parameters:
      challengeResponse - arbitrary string

    • consume

      public final void consume(Object obj)
      Consume object. This call provides a side effect preventing JIT to eliminate dependent computations.
      Parameters:
      obj - object to consume.

    • consume

      public final void consume(byte b)
      Consume object. This call provides a side effect preventing JIT to eliminate dependent computations.
      Parameters:
      b - object to consume.

    • consume

      public final void consume(boolean bool)
      Consume object. This call provides a side effect preventing JIT to eliminate dependent computations.
      Parameters:
      bool - object to consume.

    • consume

      public final void consume(char c)
      Consume object. This call provides a side effect preventing JIT to eliminate dependent computations.
      Parameters:
      c - object to consume.

    • consume

      public final void consume(short s)
      Consume object. This call provides a side effect preventing JIT to eliminate dependent computations.
      Parameters:
      s - object to consume.

    • consume

      public final void consume(int i)
      Consume object. This call provides a side effect preventing JIT to eliminate dependent computations.
      Parameters:
      i - object to consume.

    • consume

      public final void consume(long l)
      Consume object. This call provides a side effect preventing JIT to eliminate dependent computations.
      Parameters:
      l - object to consume.

    • consume

      public final void consume(float f)
      Consume object. This call provides a side effect preventing JIT to eliminate dependent computations.
      Parameters:
      f - object to consume.

    • consume

      public final void consume(double d)
      Consume object. This call provides a side effect preventing JIT to eliminate dependent computations.
      Parameters:
      d - object to consume.

    • consumeCPU

      public static void consumeCPU(long tokens)
      Consume some amount of time tokens. This method does the CPU work almost linear to the number of tokens. The token cost may vary from system to system, and may change in future. (Translation: it is as reliable as we can get, but not absolutely reliable). See JMH samples for the complete demo, and core benchmarks for the performance assessments.
      Parameters:
      tokens - CPU tokens to consume