org.palladiosimulator.experimentanalysis.windowaggregators

Class SlidingWindowExponentialSmoothingUtilizationAggregator

java.lang.Object

org.palladiosimulator.experimentanalysis.windowaggregators.SlidingWindowAggregator

org.palladiosimulator.experimentanalysis.windowaggregators.SlidingWindowUtilizationAggregator

org.palladiosimulator.experimentanalysis.windowaggregators.SlidingWindowExponentialSmoothingUtilizationAggregator

All Implemented Interfaces:

ISlidingWindowListener

public final class SlidingWindowExponentialSmoothingUtilizationAggregator
extends SlidingWindowUtilizationAggregator

This class is a specialized SlidingWindowUtilizationAggregator implementation which calculates the utilization or, (which is more precisely in the scope of this class), the average load) of an active resource based on a sequence of (point in time, state of active resource) or (point in time, utilization of active resource) tuples collected by a SlidingWindow by employing the algorithm that is used in the Linux kernel to compute the average load (Details of this algorithm can be found in this paper, or more succinctly, in this presentation both due to Neil Gunther).
The calculated load is passed to all attached IRecorders in the form of a (point in time, utilization of active resource) tuple each time this implementation processes new window data. Such a point in time is referred to as reporting period and equal to the length of the corresponding SlidingWindow.

Note: The afore-mentioned algorithm is a special case of exponential smoothing with the smoothing factor α derived from the given sampling rate and reporting period.

Author:

Florian Rosenthal

See Also:

SlidingWindowRecorder, SlidingWindowUtilizationAggregator.getAllowedWindowDataMetrics()

Constructor Summary

Constructors

Constructor and Description

SlidingWindowExponentialSmoothingUtilizationAggregator(org.palladiosimulator.metricspec.MetricDescription windowDataMetric, org.palladiosimulator.recorderframework.IRecorder recorderToWriteInto, javax.measure.Measurable<javax.measure.quantity.Duration> samplingRate, javax.measure.Measurable<javax.measure.quantity.Duration> reportingPeriod) Initializes a new instance of the SlidingWindowExponentialSmoothingUtilizationAggregator class with the given arguments.

Method Summary

Modifier and Type	Method and Description
javax.measure.Measurable<javax.measure.quantity.Duration>	getSamplingRate()
double	getSmoothingFactor()

Methods inherited from class org.palladiosimulator.experimentanalysis.windowaggregators.SlidingWindowUtilizationAggregator

getAllowedWindowDataMetrics, getExpectedWindowDataMetric

Methods inherited from class org.palladiosimulator.experimentanalysis.windowaggregators.SlidingWindowAggregator

addRecorder, onSlidingWindowFull

Methods inherited from class java.lang.Object

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

Constructor Detail

SlidingWindowExponentialSmoothingUtilizationAggregator

public SlidingWindowExponentialSmoothingUtilizationAggregator(org.palladiosimulator.metricspec.MetricDescription windowDataMetric,
                                                              org.palladiosimulator.recorderframework.IRecorder recorderToWriteInto,
                                                              javax.measure.Measurable<javax.measure.quantity.Duration> samplingRate,
                                                              javax.measure.Measurable<javax.measure.quantity.Duration> reportingPeriod)

Initializes a new instance of the SlidingWindowExponentialSmoothingUtilizationAggregator class with the given arguments.

Parameters:

windowDataMetric - The MetricDescription of the measurements to be processed, i.e, which are used to compute the utilization.

recorderToWriteInto - An IRecorder this instance writes the aggregated window data into. Typically, a recorder that writes into a persistence framework like EDP 2 is passed here.

samplingRate - An Amount denoting the sampling rate which equals the increment of the associated SlidingWindow.
For instance, if the given amount is 5s, the average load/utilization is updated every 5 seconds, starting at the window's left bound.

reportingPeriod - An Amount describing the reporting period which is simply the length of the associated SlidingWindow.
For instance, if the given amount is 1min, the computed average load/utilization is forwarded every minute to the attached recorders.

Throws:

java.lang.NullPointerException - If any of the arguments is null.

java.lang.IllegalArgumentException - If the given metric is not supported by this aggregator, or either of the given amounts is not positive.

Method Detail

getSamplingRate

public javax.measure.Measurable<javax.measure.quantity.Duration> getSamplingRate()

getSmoothingFactor

public double getSmoothingFactor()