Class Blackhole

java.lang.Object

org.openjdk.jmh.infra.BlackholeL0

org.openjdk.jmh.infra.BlackholeL1

org.openjdk.jmh.infra.BlackholeL2

org.openjdk.jmh.infra.BlackholeL3

org.openjdk.jmh.infra.BlackholeL4

org.openjdk.jmh.infra.Blackhole

public final class Blackhole
extends BlackholeL4

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 Summary

Fields

Modifier and Type	Field	Description
private static final boolean	COMPILER_BLACKHOLE
private static long	consumedCPU

Fields inherited from class BlackholeL2

b1, b2, bool1, bool2, c1, c2, d1, d2, f1, f2, i1, i2, l1, l2, nullBait, obj1, s1, s2, tlr, tlrMask

Constructor Summary

Constructors

Constructor	Description
Blackhole(String challengeResponse)

Method Summary

Modifier and Type	Method	Description
final void	consume(boolean bool)	Consume object.
final void	consume(byte b)	Consume object.
final void	consume(char c)	Consume object.
final void	consume(double d)	Consume object.
final void	consume(float f)	Consume object.
final void	consume(int i)	Consume object.
final void	consume(long l)	Consume object.
final void	consume(short s)	Consume object.
final void	consume(Object obj)	Consume object.
private static void	consumeCompiler(boolean v)
private static void	consumeCompiler(byte v)
private static void	consumeCompiler(char v)
private static void	consumeCompiler(double v)
private static void	consumeCompiler(float v)
private static void	consumeCompiler(int v)
private static void	consumeCompiler(long v)
private static void	consumeCompiler(short v)
private static void	consumeCompiler(Object v)
static void	consumeCPU(long tokens)	Consume some amount of time tokens.
private void	consumeFull(boolean bool)
private void	consumeFull(byte b)
private void	consumeFull(char c)
private void	consumeFull(double d)
private void	consumeFull(float f)
private void	consumeFull(int i)
private void	consumeFull(long l)
private void	consumeFull(short s)
private void	consumeFull(Object obj)
void	evaporate(String challengeResponse)	Make any consumed data begone.

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

COMPILER_BLACKHOLE

private static final boolean COMPILER_BLACKHOLE

consumedCPU

private static volatile long consumedCPU

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.

consumeCompiler

private static void consumeCompiler(boolean v)

consumeCompiler

private static void consumeCompiler(byte v)

consumeCompiler

private static void consumeCompiler(short v)

consumeCompiler

private static void consumeCompiler(char v)

consumeCompiler

private static void consumeCompiler(int v)

consumeCompiler

private static void consumeCompiler(float v)

consumeCompiler

private static void consumeCompiler(double v)

consumeCompiler

private static void consumeCompiler(long v)

consumeCompiler

private static void consumeCompiler(Object v)

consumeFull

private void consumeFull(byte b)

consumeFull

private void consumeFull(boolean bool)

consumeFull

private void consumeFull(char c)

consumeFull

private void consumeFull(short s)

consumeFull

private void consumeFull(int i)

consumeFull

private void consumeFull(long l)

consumeFull

private void consumeFull(float f)

consumeFull

private void consumeFull(double d)

consumeFull

private void consumeFull(Object obj)

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