com.sun.slamd.loadvariance
Class StairStepLoadVarianceAlgorithm

java.lang.Object
  com.sun.slamd.loadvariance.LoadVarianceAlgorithm
      com.sun.slamd.loadvariance.StairStepLoadVarianceAlgorithm

public class StairStepLoadVarianceAlgorithm

extends LoadVarianceAlgorithm

This class defines a load variance algorithm that may be used to increase or decrease the number of active threads in spurts rather than gradually over time. That is, all the threads to enable or disable will be notified at the very beginning of the interval with no change over the duration of that interval. That is, the graph will appear to have an initial jump up or down but then will remain level for the duration of the interval associated with that line. The change in the number of active threads may be specified in one of the following ways:

• "+N", where N is a fixed number of threads to start at the beginning of this load variation.
• "-N", where N is a fixed number of threads to stop at the beginning of this load variation.
• "+N%", where N% is a percentage of the overall number of threads per client that should be started at the beginning of this load variation.
• "-N%", where N% is a percentage of the overall number of threads per client that should be stopped at the beginning of this load variation.
• "=N", where N is the fixed number of threads that should be running once this load variation completes.
• "=N%", where N% is a percentage of the overall number of threads per client that should be running once this load variation completes.

Field Summary

static int	METHOD_DECREASE_BY_NUMBER The variation method that indicates that the number of active threads should be decreased by a fixed amount.
static int	METHOD_DECREASE_BY_PERCENT The variation method that indicates that the number of active threads should be decreased by a percentage of the total number of threads.
static int	METHOD_INCREASE_BY_NUMBER The variation method that indicates that the number of active threads should be increased by a fixed amount.
static int	METHOD_INCREASE_BY_PERCENT The variation method that indicates that the number of active threads should be increased by a percentage of the total number of threads.
static int	METHOD_SET_TO_NUMBER The variation method that indicates that the number of active threads should be set to a fixed number.
static int	METHOD_SET_TO_PERCENT The variation method that indicates that the number of active threads should be set to a percentage of the total number of threads.

Constructor Summary

StairStepLoadVarianceAlgorithm()
This constructor is used to create a new instance of this load variation algorithm through reflection.

Method Summary

int[][]	calculateVariance(int duration, int totalThreads, int activeThreads) Retrieves a two-dimensional array that provides information about the increase or decrease in active job threads that should be applied over time.
void	initializeVariationAlgorithm(java.lang.String[] arguments) Initializes this load variation algorithm based on the provided list of arguments.

Methods inherited from class java.lang.Object

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

Field Detail

METHOD_INCREASE_BY_NUMBER

public static final int METHOD_INCREASE_BY_NUMBER

The variation method that indicates that the number of active threads should be increased by a fixed amount.

See Also:

Constant Field Values

METHOD_DECREASE_BY_NUMBER

public static final int METHOD_DECREASE_BY_NUMBER

The variation method that indicates that the number of active threads should be decreased by a fixed amount.

See Also:

Constant Field Values

METHOD_INCREASE_BY_PERCENT

public static final int METHOD_INCREASE_BY_PERCENT

The variation method that indicates that the number of active threads should be increased by a percentage of the total number of threads.

See Also:

Constant Field Values

METHOD_DECREASE_BY_PERCENT

public static final int METHOD_DECREASE_BY_PERCENT

The variation method that indicates that the number of active threads should be decreased by a percentage of the total number of threads.

See Also:

Constant Field Values

METHOD_SET_TO_NUMBER

public static final int METHOD_SET_TO_NUMBER

The variation method that indicates that the number of active threads should be set to a fixed number.

See Also:

Constant Field Values

METHOD_SET_TO_PERCENT

public static final int METHOD_SET_TO_PERCENT

The variation method that indicates that the number of active threads should be set to a percentage of the total number of threads.

See Also:

Constant Field Values

Constructor Detail

StairStepLoadVarianceAlgorithm

public StairStepLoadVarianceAlgorithm()

This constructor is used to create a new instance of this load variation algorithm through reflection. A default constructor must be provided in all subclasses, but the only thing that it needs to do is call super().

Method Detail

initializeVariationAlgorithm

public void initializeVariationAlgorithm(java.lang.String[] arguments)
                                  throws SLAMDException

Initializes this load variation algorithm based on the provided list of arguments.

Specified by:

initializeVariationAlgorithm in class LoadVarianceAlgorithm

Parameters:

arguments - The arguments that may be used to customize the behavior of this load variation algorithm.

Throws:

SLAMDException - If a problem occurs while trying to initialize this load variation algorithm.

calculateVariance

public int[][] calculateVariance(int duration,
                                 int totalThreads,
                                 int activeThreads)
                          throws SLAMDException

Retrieves a two-dimensional array that provides information about the increase or decrease in active job threads that should be applied over time. Each element of the array returned should itself be a two-element array with the first element being the number of milliseconds since the start of this load variance instruction that the increase or decrease should occur, and the second is an integer value that indicates the number of threads that should be added at that time (may be negative if threads are to be removed).

Specified by:

calculateVariance in class LoadVarianceAlgorithm

Parameters:

duration - The length of time in seconds over which this load variance algorithm should operate.

totalThreads - The total number of threads that have been scheduled for the job with which this algorithm is to be used.

activeThreads - The number of threads that are already active at the time that this method is called.

Returns:

A two-dimensional array that provides information about the increase or decrease in active job threads that should be applied over time.

Throws:

SLAMDException