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 Summary

Fields

Modifier and Type	Field	Description
byte	b1
byte	b2
boolean	bool1
boolean	bool2
char	c1
char	c2
double	d1
double	d2
float	f1
float	f2
int	i1
int	i2
long	l1
long	l2
org.openjdk.jmh.infra.BlackholeL2	nullBait
Object	obj1
short	s1
short	s2
int	tlr
int	tlrMask

Constructor Summary

Constructors

Constructor	Description
Blackhole(String challengeResponse)

Method Summary

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

Methods inherited from class java.lang.Object

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

Field Detail

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 Detail

Blackhole

public Blackhole(String challengeResponse)

Method Detail

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