ptolemy.domains.giotto.kernel

Class GiottoTimingManager

java.lang.Object

ptolemy.kernel.util.NamedObj

ptolemy.kernel.util.Attribute

ptolemy.kernel.util.SingletonAttribute

ptolemy.domains.giotto.kernel.GiottoTimingManager

All Implemented Interfaces:

java.lang.Cloneable, Changeable, Debuggable, DebugListener, Decorator, Derivable, ModelErrorHandler, MoMLExportable, Moveable, Nameable, Singleton

public class GiottoTimingManager
extends SingletonAttribute
implements Decorator

An attribute that varies the WCET values of actors and throws a model error if the sum of the execution times is larger than the sum of the worst case execution times.

This attribute helps the user to manage and mitigate timing errors in a specification that uses timing but has no mechanisms in its specification for timing error handling. In this context a timing error occurs if the actor takes more than the specified WCET to execute.

The presence of the timing manager indicates a desire to incorporate execution timing as well as error handling into a Giotto specification.

This attribute is a decorator that adds a parameter to each actor at the current level. The parameter is named WCET, which is the Worst Case Execution Time (WCET) for the actor whose initial default value is 0.0. This indicates instantaneous execution, however, for each actor this parameter can also be modified by the user with information gained from an external WCET analysis tool.

This class simulates timing overruns by varying the execution time of each actor. It currently uses the java.util.Random pseudo random number generator to generate a random execution time in the range [0,2*WCET] for each iteration of each actor. The random number generator can be seeded by the seed parameter. The default value of the seed is 0L interpreted as not having a seed. The user also has the option to reset to the seed on each run by selecting the resetOnEachRun parameter. A future modification could include adding a parameter to have the user specify what probability distribution they wish to use.

This attribute checks for two types of errors. First, it does a static check of (a) the sum of the worst case execution times for the actors and compares (a) to the GiottoDirector.period of the Giotto Director. If (a) is larger than the director period, then the attribute throws an exception notifying the user of the discrepancy and does not execute the model. Second, during execution the attribute randomly varies the execution time of the actors. The attribute then compares (b) the sum of the actors execution times to (a) the sum of the actors worst case execution times. If (a) < (b) then the attribute calls NamedObj.handleModelError(NamedObj, IllegalActionException), which throws a model error .

A model error is an exception that is passed up the containment hierarchy rather than being immediately thrown. Any container in the containment hierarchy may choose to handle the error. By default, containers will pass and delegate the error to their container, if they have one, and throw an exception if they don't. But some containers might do more with the error.

The attribute can be instantiated by instantiating an attribute of type GiottoTimingManager.

Since:

Ptolemy II 10.0

Version:

$Id$

Author:

Shanna-Shaye Forbes. Based on the MonitorReceiverContents.java created by Edward A. Lee and RandomSource.java by Edward A. Lee, Steve Neuendorffer, Elaine Cheong

Pt.AcceptedRating:

Red (sssf)

Pt.ProposedRating:

Red (sssf)

Nested Class Summary

Nested classes/interfaces inherited from class ptolemy.kernel.util.NamedObj

NamedObj.ContainedObjectsIterator

Field Summary

Fields

Modifier and Type	Field and Description
protected double	_current The Current value of the randomly generated number.
protected long	_generatorSeed The current value of the seed parameter.
protected boolean	_needNew Indicator that a new random number is needed.
protected boolean	_needNewGenerator Indicator that a new generator is needed.
protected java.util.Random	_random The Random object.
StringParameter	probabilityDistribution The value that controls the type of the probability distribution used for random number generation.
SharedParameter	resetOnEachRun If true, this parameter specifies that the random number generator should be reset on each run of the model (in the initialize() method).
SharedParameter	seed The seed that controls the random number generation.

Fields inherited from class ptolemy.kernel.util.NamedObj

_changeListeners, _changeLock, _changeRequests, _debugging, _debugListeners, _deferChangeRequests, _elementName, _isPersistent, _verbose, _workspace, ATTRIBUTES, CLASSNAME, COMPLETE, CONTENTS, DEEP, FULLNAME, LINKS

Constructor Summary

Constructors

Constructor and Description
GiottoTimingManager(NamedObj container, java.lang.String name) Construct an instance with the specified container and name.

Method Summary

Modifier and Type	Method and Description
protected void	_createGenerator() Create the random number generator using current parameter values.
protected void	_generateRandomNumber() Generate the next random number.
void	attributeChanged(Attribute attribute) If the attribute is seed then create the base random number generator.
DecoratorAttributes	createDecoratorAttributes(NamedObj target) Return the decorated attributes for the target NamedObj.
java.util.List<NamedObj>	decoratedObjects() Return a list of the entities deeply contained by the container of this resource scheduler.
boolean	isGlobalDecorator() Return false to indicate that this decorator should not decorate objects across opaque hierarchy boundaries.
void	setContainer(NamedObj container) Specify the container.

Methods inherited from class ptolemy.kernel.util.Attribute

_checkContainer, _getContainedObject, _propagateExistence, clone, getContainer, moveDown, moveToFirst, moveToIndex, moveToLast, moveUp, setName, updateContent

Methods inherited from class ptolemy.kernel.util.NamedObj

_addAttribute, _adjustOverride, _attachText, _cloneFixAttributeFields, _containedDecorators, _copyChangeRequestList, _debug, _debug, _debug, _debug, _debug, _description, _executeChangeRequests, _exportMoMLContents, _getIndentPrefix, _isMoMLSuppressed, _markContentsDerived, _notifyHierarchyListenersAfterChange, _notifyHierarchyListenersBeforeChange, _propagateValue, _removeAttribute, _splitName, _stripNumericSuffix, _validateSettables, addChangeListener, addDebugListener, addHierarchyListener, attributeDeleted, attributeList, attributeList, attributeTypeChanged, clone, containedObjectsIterator, decorators, deepContains, depthInHierarchy, description, description, event, executeChangeRequests, exportMoML, exportMoML, exportMoML, exportMoML, exportMoML, exportMoMLPlain, getAttribute, getAttribute, getAttributes, getChangeListeners, getClassName, getDecoratorAttribute, getDecoratorAttributes, getDerivedLevel, getDerivedList, getDisplayName, getElementName, getFullName, getModelErrorHandler, getName, getName, getPrototypeList, getSource, handleModelError, isDeferringChangeRequests, isOverridden, isPersistent, lazyContainedObjectsIterator, message, notifyOfNameChange, propagateExistence, propagateValue, propagateValues, removeAttribute, removeChangeListener, removeDebugListener, removeHierarchyListener, requestChange, setClassName, setDeferringChangeRequests, setDerivedLevel, setDisplayName, setModelErrorHandler, setPersistent, setSource, sortContainedObjects, toplevel, toString, uniqueName, validateSettables, workspace

Methods inherited from class java.lang.Object

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

Methods inherited from interface ptolemy.kernel.util.Nameable

description, getContainer, getDisplayName, getFullName, getName, getName, setName

Field Detail

resetOnEachRun

public SharedParameter resetOnEachRun

If true, this parameter specifies that the random number generator should be reset on each run of the model (in the initialize() method). It is a boolean that defaults to false. This is a shared parameter, meaning that changing it somewhere in the model causes it to be changed everywhere in the model.

seed

public SharedParameter seed

The seed that controls the random number generation. This is a shared parameter, meaning that all instances of RandomSource or derived classes in the same model share the same value. A seed of zero is interpreted to mean that no seed is specified, which means that each execution of the model could result in distinct data. For the value 0, the seed is set to System.currentTimeMillis() + hashCode(), which means that with extremely high probability, two distinct actors will have distinct seeds. However, current time may not have enough resolution to ensure that two subsequent executions of the same model have distinct seeds. For a value other than zero, the seed is set to that value plus the hashCode() of the full name of the actor. This means that with high probability, two distinct actors will have distinct, but repeatable seeds. This parameter contains a LongToken, initially with value 0.

probabilityDistribution

public StringParameter probabilityDistribution

The value that controls the type of the probability distribution used for random number generation. The probability distribution defaults to none, which is interpreted as an equal distribution of numbers between 0 and 1.

_generatorSeed

protected long _generatorSeed

The current value of the seed parameter.

_needNewGenerator

protected boolean _needNewGenerator

Indicator that a new generator is needed.

_random

protected java.util.Random _random

The Random object.

_needNew

protected boolean _needNew

Indicator that a new random number is needed.

_current

protected double _current

The Current value of the randomly generated number.

Constructor Detail

GiottoTimingManager

public GiottoTimingManager(NamedObj container,
                           java.lang.String name)
                    throws IllegalActionException,
                           NameDuplicationException

Construct an instance with the specified container and name.

Parameters:

container - The container.

name - The name of this actor.

Throws:

IllegalActionException - If the entity cannot be contained by the proposed container.

NameDuplicationException - If the container already has an actor with this name.

Method Detail

attributeChanged

public void attributeChanged(Attribute attribute)
                      throws IllegalActionException

If the attribute is seed then create the base random number generator.

Overrides:

attributeChanged in class NamedObj

Parameters:

attribute - The attribute that changed.

Throws:

IllegalActionException - If the change is not acceptable to this container (not thrown in this base class).

createDecoratorAttributes

public DecoratorAttributes createDecoratorAttributes(NamedObj target)

Return the decorated attributes for the target NamedObj.

Specified by:

createDecoratorAttributes in interface Decorator

Parameters:

target - The NamedObj that will be decorated.

Returns:

The decorated attributes for the target NamedObj.

decoratedObjects

public java.util.List<NamedObj> decoratedObjects()

Return a list of the entities deeply contained by the container of this resource scheduler.

Specified by:

decoratedObjects in interface Decorator

Returns:

A list of the objects decorated by this decorator.

isGlobalDecorator

public boolean isGlobalDecorator()

Return false to indicate that this decorator should not decorate objects across opaque hierarchy boundaries.

Specified by:

isGlobalDecorator in interface Decorator

Returns:

True if decorator is global.

setContainer

public void setContainer(NamedObj container)
                  throws IllegalActionException,
                         NameDuplicationException

Specify the container. If the container is not the same as the previous container, then start monitoring the new container.

Overrides:

setContainer in class SingletonAttribute

Parameters:

container - The container to attach this attribute to..

Throws:

IllegalActionException - If this attribute is not of the expected class for the container, or it has no name, or the attribute and container are not in the same workspace, or the proposed container would result in recursive containment.

NameDuplicationException - If the container already has an attribute with the name of this attribute.

See Also:

Attribute.getContainer()

_createGenerator

protected void _createGenerator()
                         throws IllegalActionException

Create the random number generator using current parameter values.

Throws:

IllegalActionException - If thrown while reading the seed Token.

_generateRandomNumber

protected void _generateRandomNumber()
                              throws IllegalActionException

Generate the next random number.

Throws:

IllegalActionException - Not thrown in this base class.