Package org.apache.hadoop.ipc

Class WeightedRoundRobinMultiplexer

java.lang.Object

org.apache.hadoop.ipc.WeightedRoundRobinMultiplexer

All Implemented Interfaces:

RpcMultiplexer

public class WeightedRoundRobinMultiplexer
extends java.lang.Object
implements RpcMultiplexer

Determines which queue to start reading from, occasionally drawing from low-priority queues in order to prevent starvation. Given the pull pattern [9, 4, 1] for 3 queues: The cycle is (a minimum of) 9+4+1=14 reads. Queue 0 is read (at least) 9 times Queue 1 is read (at least) 4 times Queue 2 is read (at least) 1 time Repeat There may be more reads than the minimum due to race conditions. This is allowed by design for performance reasons.

Field Summary

Fields

Modifier and Type	Field	Description
static java.lang.String	IPC_CALLQUEUE_WRRMUX_WEIGHTS_KEY
static org.slf4j.Logger	LOG

Constructor Summary

Constructors

Constructor	Description
WeightedRoundRobinMultiplexer(int aNumQueues, java.lang.String ns, Configuration conf)

Method Summary

Modifier and Type	Method	Description
int	getAndAdvanceCurrentIndex()	Use the mux by getting and advancing index.

Methods inherited from class java.lang.Object

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

Field Detail

IPC_CALLQUEUE_WRRMUX_WEIGHTS_KEY

public static final java.lang.String IPC_CALLQUEUE_WRRMUX_WEIGHTS_KEY

See Also:

Constant Field Values

LOG

public static final org.slf4j.Logger LOG

Constructor Detail

WeightedRoundRobinMultiplexer

public WeightedRoundRobinMultiplexer(int aNumQueues,
                                     java.lang.String ns,
                                     Configuration conf)

Method Detail

getAndAdvanceCurrentIndex

public int getAndAdvanceCurrentIndex()

Use the mux by getting and advancing index.

Specified by:

getAndAdvanceCurrentIndex in interface RpcMultiplexer

Returns:

current index