javolution.test

Class Perfometer<T>

java.lang.Object

javolution.test.Perfometer<T>

Type Parameters:

T - the perfometer input type.

public abstract class Perfometer<T>
extends Object

Utility class to measure the worst case execution time and average execution time with high precision. Here an example measuring the worst case execution time of List.add(int, Object) for diverse list implementations.

 Perfometer<Class<? extends List>> insertPerf = new Perfometer<>("java.util.List#add(int, Object)") {
     List<Object> list;
     Random random;
     protected void initialize() throws Exception {
          list = getInput().newInstance();
          random = new Random(-1); // Use seed to ensure same execution path.
     }
     protected void run(boolean measure) {
          Object obj = new Object();
          int i = random.nextInt(list.size() + 1);
          if (measure) list.add(i, obj);
     }
     protected void validate() { // Optional.
         assert list.size() == getNbrOfIterations();
     }
 }
 ...
 public void testExecutionTime() {
     insertPerf.measure(java.util.ArrayList.class, 10000).print();
     insertPerf.measure(java.util.LinkedList.class, 10000).print();
     insertPerf.measure(javolution.util.FastTable.class, 10000).print();
 }
 ...
 > [INFO] java.util.List#add(int, Object) (10000) for java.util.ArrayList:       590.21450 ns (avg), 8443.0000 ns (wcet#9369)
 > [INFO] java.util.List#add(int, Object) (10000) for java.util.LinkedList:      4849.8313 ns (avg), 26536.000 ns (wcet#9863)
 > [INFO] java.util.List#add(int, Object) (10000) for javolution.util.FastTable: 217.26300 ns (avg), 534.00000 ns (wcet#8864)
 

Field Summary

Fields

Modifier and Type	Field and Description
static Configurable<Integer>	DURATION_MS Hold the measurement duration in milliseconds (default 1000 ms).
static Configurable<Boolean>	SKIP Indicates if perfometer measurements should be skipped ( e.g.

Constructor Summary

Constructors

Constructor and Description
Perfometer(String description) Creates a perfometer having the specified description.

Method Summary

Methods

Modifier and Type	Method and Description
double	getAvgTimeInSeconds() Returns the average execution time in seconds.
String	getDescription() Returns this perfometer description.
T	getInput() Returns this perfometer current inputs.
int	getNbrOfIterations() Returns this perfometer current number of iterations performed.
double[]	getTimesInSeconds() Returns the execution times in seconds.
double	getWCETinSeconds() Returns the worst case execution time in seconds.
int	getWorstCaseNumber() Returns the iteration number having the slowest execution time.
protected abstract void	initialize() Performs the initialization.
Perfometer<T>	measure(T input, int nbrOfIterations) Measures the worst case execution time and average execution time.
void	print() Outputs the result.
void	printDetails() Outputs the measurements in nanoseconds.
protected abstract void	run(boolean measure) Runs the code being benchmarked.
protected void	validate() Validates the final result (after all iterations are completed).

Methods inherited from class java.lang.Object

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

Field Detail

DURATION_MS

public static final Configurable<Integer> DURATION_MS

Hold the measurement duration in milliseconds (default 1000 ms).

SKIP

public static final Configurable<Boolean> SKIP

Indicates if perfometer measurements should be skipped ( e.g. -Djavolution.test.Perfometer#SKIP=true to skip performance measurements). When skipped, measure(T, int) and print() don't do anything.

Constructor Detail

Perfometer

public Perfometer(String description)

Creates a perfometer having the specified description.

Parameters:

description - the description of the code being measured.

Method Detail

getAvgTimeInSeconds

public double getAvgTimeInSeconds()

Returns the average execution time in seconds.

getDescription

public String getDescription()

Returns this perfometer description.

getInput

public T getInput()

Returns this perfometer current inputs.

getNbrOfIterations

public int getNbrOfIterations()

Returns this perfometer current number of iterations performed.

getTimesInSeconds

public double[] getTimesInSeconds()

Returns the execution times in seconds.

measure

public Perfometer<T> measure(T input,
                    int nbrOfIterations)

Measures the worst case execution time and average execution time.

Parameters:

input - the test input.

nbrOfIterations - the number of iterations performed on which the average will be calculated.

print

public void print()

Outputs the result.

printDetails

public void printDetails()

Outputs the measurements in nanoseconds.

getWCETinSeconds

public double getWCETinSeconds()

Returns the worst case execution time in seconds.

getWorstCaseNumber

public int getWorstCaseNumber()

Returns the iteration number having the slowest execution time.

initialize

protected abstract void initialize()
                            throws Exception

Performs the initialization.

Throws:

Exception

run

protected abstract void run(boolean measure)
                     throws Exception

Runs the code being benchmarked.

Parameters:

measure - false when calibration is performed; true otherwise.

Throws:

Exception

validate

protected void validate()

Validates the final result (after all iterations are completed).