org.apache.giraph.comm.flow_control

Class StaticFlowControl

java.lang.Object

org.apache.giraph.comm.flow_control.StaticFlowControl

All Implemented Interfaces:

FlowControl, ResetSuperstepMetricsObserver

public class StaticFlowControl
extends Object
implements FlowControl, ResetSuperstepMetricsObserver

Representation of a flow control that limits the aggregate number of open requests to all other workers to a constant user-defined value

Field Summary

Fields

Modifier and Type	Field and Description
static FloatConfOption	FRACTION_OF_REQUESTS_TO_CLOSE_BEFORE_PROCEEDING After pausing a thread due to too large number of open requests, which fraction of these requests need to be closed before we continue
static IntConfOption	MAX_NUMBER_OF_OPEN_REQUESTS Maximum number of requests without confirmation we should have

Constructor Summary

Constructors

Constructor and Description
StaticFlowControl(ImmutableClassesGiraphConfiguration conf, NettyClient nettyClient) Constructor

Method Summary

Modifier and Type	Method and Description
int	calculateResponse(AckSignalFlag alreadyDone, int clientId) Calculate/Build the response to piggyback with acknowledgement
AckSignalFlag	getAckSignalFlag(int response) Decode the acknowledgement signal from the response after an open request is completed
int	getNumberOfUnsentRequests()
void	logInfo() Log the status of the flow control
void	messageAckReceived(int taskId, long requestId, int response) Notify the flow control policy that an open request is completed.
void	newSuperstep(SuperstepMetricsRegistry metrics) Starting a new superstep.
void	sendRequest(int destTaskId, WritableRequest request) This method is called by a network client for all requests that should be handled by a *remote* task.
void	waitAllRequests() There may be requests in possession of the flow control mechanism, as the mechanism controls whether a task should send a request or not.

Methods inherited from class java.lang.Object

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

Field Detail

MAX_NUMBER_OF_OPEN_REQUESTS

public static final IntConfOption MAX_NUMBER_OF_OPEN_REQUESTS

Maximum number of requests without confirmation we should have

FRACTION_OF_REQUESTS_TO_CLOSE_BEFORE_PROCEEDING

public static final FloatConfOption FRACTION_OF_REQUESTS_TO_CLOSE_BEFORE_PROCEEDING

After pausing a thread due to too large number of open requests, which fraction of these requests need to be closed before we continue

Constructor Detail

StaticFlowControl

public StaticFlowControl(ImmutableClassesGiraphConfiguration conf,
                         NettyClient nettyClient)

Constructor

Parameters:

conf - configuration

nettyClient - netty client

Method Detail

newSuperstep

public void newSuperstep(SuperstepMetricsRegistry metrics)

Description copied from interface: ResetSuperstepMetricsObserver

Starting a new superstep. Re-initialize your metrics.

Specified by:

newSuperstep in interface ResetSuperstepMetricsObserver

Parameters:

metrics - SuperstepMetricsRegistry being used.

sendRequest

public void sendRequest(int destTaskId,
                        WritableRequest request)

Description copied from interface: FlowControl

This method is called by a network client for all requests that should be handled by a *remote* task. All these requests should be controlled and/or monitored by the flow control policy. The flow control policy may choose to temporarily hold off from sending to a particular remote task and keep the request in some cache for later transfer. A flow control mechanism is free to implement this method as blocking or non-blocking. Note that, a flow-control policy should adhere to exactly-once semantic, meaning it should always send one and only one copy of each request that should be handled by a remote task.

Specified by:

sendRequest in interface FlowControl

Parameters:

destTaskId - id of the worker to send the request to

request - request to send

messageAckReceived

public void messageAckReceived(int taskId,
                               long requestId,
                               int response)

Description copied from interface: FlowControl

Notify the flow control policy that an open request is completed.

Specified by:

messageAckReceived in interface FlowControl

Parameters:

taskId - id of the task to which the open request is completed

requestId - id of the open request which is completed

response - the response heard from the client

getAckSignalFlag

public AckSignalFlag getAckSignalFlag(int response)

Description copied from interface: FlowControl

Decode the acknowledgement signal from the response after an open request is completed

Specified by:

getAckSignalFlag in interface FlowControl

Parameters:

response - the response heard after completion of a request

Returns:

the Acknowledgement signal decoded from the response

calculateResponse

public int calculateResponse(AckSignalFlag alreadyDone,
                             int clientId)

Description copied from interface: FlowControl

Calculate/Build the response to piggyback with acknowledgement

Specified by:

calculateResponse in interface FlowControl

Parameters:

alreadyDone - indicating the status of processing of the request (whether it was a new request or it was a duplicate)

clientId - id of the task the acknowledgement is for

Returns:

the response to piggyback along with the acknowledgement message

logInfo

public void logInfo()

Description copied from interface: FlowControl

Log the status of the flow control

Specified by:

logInfo in interface FlowControl

waitAllRequests

public void waitAllRequests()

Description copied from interface: FlowControl

There may be requests in possession of the flow control mechanism, as the mechanism controls whether a task should send a request or not. Calling this method causes the caller to wait until all requests in possession of the flow control mechanism are sent out.

Specified by:

waitAllRequests in interface FlowControl

getNumberOfUnsentRequests

public int getNumberOfUnsentRequests()

Specified by:

getNumberOfUnsentRequests in interface FlowControl

Returns:

number of unsent requests in possession of the flow control policy