org.apache.giraph.comm.flow_control

Interface FlowControl

All Known Implementing Classes:

CreditBasedFlowControl, NoOpFlowControl, StaticFlowControl

public interface FlowControl

Interface representing flow control policy in sending requests

Method Summary

Modifier and Type	Method and Description
int	calculateResponse(AckSignalFlag flag, int taskId) 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	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.

Method Detail

sendRequest

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. 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.

Parameters:

destTaskId - id of the worker to send the request to

request - request to send

messageAckReceived

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

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

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

AckSignalFlag getAckSignalFlag(int response)

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

Parameters:

response - the response heard after completion of a request

Returns:

the Acknowledgement signal decoded from the response

waitAllRequests

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. Calling this method causes the caller to wait until all requests in possession of the flow control mechanism are sent out.

getNumberOfUnsentRequests

int getNumberOfUnsentRequests()

Returns:

number of unsent requests in possession of the flow control policy

calculateResponse

int calculateResponse(AckSignalFlag flag,
                      int taskId)

Calculate/Build the response to piggyback with acknowledgement

Parameters:

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

taskId - id of the task the acknowledgement is for

Returns:

the response to piggyback along with the acknowledgement message

logInfo

void logInfo()

Log the status of the flow control