ec.eval

Class SlaveMonitor

java.lang.Object

ec.eval.SlaveMonitor

public class SlaveMonitor
extends Object

SlaveMonitor.java

The SlaveMonitor manages slave connections to each remote slave, and provides synchronization facilities for the slave connections and for various other objects waiting to be notified when new slaves are available, space is available in a slave's job queue, an individual has been completed, etc.

The monitor provides functions to create and delete slaves (registerSlave(), unregisterSlave()), schedule a job for evaluation (scheduleJobForEvaluation(...)), block until all jobs have completed (waitForAllSlavesToFinishEvaluating(...)), test if any individual in a job has been finished (evaluatedIndividualAvailable()), and block until an individual in a job is available and returned (waitForindividual()).

Generally speaking, the SlaveMonitor owns the SlaveConnections -- no one else should speak to them. Also generally speaking, only MasterProblems create and speak to the SlaveMonitor.

Version:

1.0

Author:

Sean Luke, Liviu Panait, and Keith Sullivan

Field Summary

Fields

Modifier and Type	Field and Description
(package private) LinkedList	allSlaves
(package private) LinkedList	availableSlaves
(package private) LinkedList	evaluatedIndividuals
(package private) int	maxJobsPerSlave
static String	P_EVALCOMPRESSION
static String	P_EVALMASTERPORT
static String	P_MAXIMUMNUMBEROFCONCURRENTJOBSPERSLAVE
static String	P_RESCHEDULELOSTJOBS
(package private) ThreadPool	pool
(package private) int	randomSeed
(package private) boolean	rescheduleLostJobs
static int	SEED_INCREMENT
ServerSocket	servSock The socket where slaves connect.
(package private) boolean	showDebugInfo
(package private) boolean	shutdownInProgress
(package private) Object[]	shutdownInProgressLock
(package private) int	slaveNum A counter used to give slaves unique numbers so they can construct useful unique names for themselves.
EvolutionState	state
(package private) Thread	thread
boolean	useCompression Indicates whether compression is used over the socket IO streams.

Constructor Summary

Constructors

Constructor and Description
SlaveMonitor(EvolutionState state, boolean showDebugInfo, MasterProblem problemPrototype) Simple constructor that initializes the data structures for keeping track of the state of each slave.

Method Summary

Methods

Modifier and Type	Method and Description
(package private) void	debug(String s)
boolean	evaluatedIndividualAvailable()
(package private) boolean	isShutdownInProgress()
void	notifyMonitor(Object monitor)
(package private) void	notifySlaveAvailability(SlaveConnection slave, Job job, EvolutionState state) Notifies the monitor that the particular slave has finished performing a job, and it (probably) is available for other jobs.
(package private) int	numAvailableSlaves() Returns the number of available slave (not busy)
(package private) void	readObject(ObjectInputStream in)
boolean	registerSlave(EvolutionState state, String name, Socket socket, DataOutputStream out, DataInputStream in) Registers a new slave with the monitor.
void	scheduleJobForEvaluation(EvolutionState state, Job job) Schedules a job for execution on one of the available slaves.
(package private) void	setShutdownInProgress(boolean val)
void	shutdown() Shuts down the slave monitor (also shuts down all slaves).
void	unregisterSlave(SlaveConnection slave) Unregisters a dead slave from the monitor.
void	waitForAllSlavesToFinishEvaluating(EvolutionState state) This method returns only when all slaves have finished the jobs that they were assigned.
QueueIndividual	waitForIndividual() Blocks until an individual comes available
boolean	waitOnMonitor(Object monitor)
(package private) void	writeObject(ObjectOutputStream out)

Methods inherited from class java.lang.Object

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

Field Detail

P_EVALMASTERPORT

public static final String P_EVALMASTERPORT

See Also:

Constant Field Values

P_EVALCOMPRESSION

public static final String P_EVALCOMPRESSION

See Also:

Constant Field Values

P_MAXIMUMNUMBEROFCONCURRENTJOBSPERSLAVE

public static final String P_MAXIMUMNUMBEROFCONCURRENTJOBSPERSLAVE

See Also:

Constant Field Values

P_RESCHEDULELOSTJOBS

public static final String P_RESCHEDULELOSTJOBS

See Also:

Constant Field Values

SEED_INCREMENT

public static final int SEED_INCREMENT

See Also:

Constant Field Values

state

public EvolutionState state

rescheduleLostJobs

boolean rescheduleLostJobs

pool

ThreadPool pool

slaveNum

int slaveNum

A counter used to give slaves unique numbers so they can construct useful unique names for themselves.

servSock

public ServerSocket servSock

The socket where slaves connect.

useCompression

public boolean useCompression

Indicates whether compression is used over the socket IO streams.

shutdownInProgress

boolean shutdownInProgress

shutdownInProgressLock

Object[] shutdownInProgressLock

randomSeed

int randomSeed

thread

Thread thread

allSlaves

LinkedList allSlaves

availableSlaves

LinkedList availableSlaves

maxJobsPerSlave

int maxJobsPerSlave

showDebugInfo

boolean showDebugInfo

evaluatedIndividuals

LinkedList evaluatedIndividuals

Constructor Detail

SlaveMonitor

public SlaveMonitor(EvolutionState state,
            boolean showDebugInfo,
            MasterProblem problemPrototype)

Simple constructor that initializes the data structures for keeping track of the state of each slave. The constructor receives two parameters: a boolean flag indicating whether the system should display information that is useful for debugging, and the maximum load per slave (the maximum number of jobs that a slave can be entrusted with at each time).

Method Detail

isShutdownInProgress

final boolean isShutdownInProgress()

setShutdownInProgress

final void setShutdownInProgress(boolean val)

waitOnMonitor

public boolean waitOnMonitor(Object monitor)

notifyMonitor

public void notifyMonitor(Object monitor)

debug

final void debug(String s)

registerSlave

public boolean registerSlave(EvolutionState state,
                    String name,
                    Socket socket,
                    DataOutputStream out,
                    DataInputStream in)

Registers a new slave with the monitor. Upon registration, a slave is marked as available for jobs.

unregisterSlave

public void unregisterSlave(SlaveConnection slave)

Unregisters a dead slave from the monitor.

shutdown

public void shutdown()

Shuts down the slave monitor (also shuts down all slaves).

scheduleJobForEvaluation

public void scheduleJobForEvaluation(EvolutionState state,
                            Job job)

Schedules a job for execution on one of the available slaves. The monitor waits until at least one slave is available to perform the job.

waitForAllSlavesToFinishEvaluating

public void waitForAllSlavesToFinishEvaluating(EvolutionState state)

This method returns only when all slaves have finished the jobs that they were assigned. While this method waits, new jobs can be assigned to the slaves. This method is usually invoked from MasterProblem.finishEvaluating. You should not abuse using this method: if there are two evaluation threads, where one of them waits until all jobs are finished, while the second evaluation thread keeps posting jobs to the slaves, the first thread might have to wait until the second thread has had all its jobs finished.

notifySlaveAvailability

void notifySlaveAvailability(SlaveConnection slave,
                           Job job,
                           EvolutionState state)

Notifies the monitor that the particular slave has finished performing a job, and it (probably) is available for other jobs.

evaluatedIndividualAvailable

public boolean evaluatedIndividualAvailable()

waitForIndividual

public QueueIndividual waitForIndividual()

Blocks until an individual comes available

numAvailableSlaves

int numAvailableSlaves()

Returns the number of available slave (not busy)

writeObject

void writeObject(ObjectOutputStream out)
           throws IOException

Parameters:

s - checkpoint file output stream

Throws:

IOException

readObject

void readObject(ObjectInputStream in)
          throws IOException,
                 ClassNotFoundException

Parameters:

s - checkpoint file input stream.

Throws:

IOException

ClassNotFoundException