com.hazelcast.internal.networking.nio.iobalancer

Class IOBalancer

java.lang.Object

com.hazelcast.internal.networking.nio.iobalancer.IOBalancer

public class IOBalancer
extends Object

It attempts to detect and fix a selector imbalance problem. By default Hazelcast uses 3 threads to read data from TCP connections and 3 threads to write data to connections. We have measured significant fluctuations of performance when the threads are not utilized equally. IOBalancer tries to detect such situations and fix them by moving NioChannelReader and NioChannelWriter between NioThread instances. It measures number of events serviced by each handler in a given interval and if imbalance is detected then it schedules handler migration to fix the situation. The exact migration strategy can be customized via MigrationStrategy. Measuring interval can be customized via GroupProperty.IO_BALANCER_INTERVAL_SECONDS It doesn't leverage ConnectionListener capability provided by ConnectionManager to observe connections as it has to be notified right after a physical TCP connection is created whilst ConnectionListener is notified only after a successful (Hazelcast) binding process.

Constructor Summary

Constructors

Constructor and Description
IOBalancer(NioThread[] inputThreads, NioThread[] outputThreads, String hzName, int balancerIntervalSeconds, LoggingService loggingService)

Method Summary

Modifier and Type	Method and Description
void	channelAdded(MigratableHandler readHandler, MigratableHandler writeHandler)
void	channelRemoved(MigratableHandler readHandler, MigratableHandler writeHandler)
void	signalMigrationComplete()
void	start()
void	stop()

Methods inherited from class java.lang.Object

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

Constructor Detail

IOBalancer

public IOBalancer(NioThread[] inputThreads,
                  NioThread[] outputThreads,
                  String hzName,
                  int balancerIntervalSeconds,
                  LoggingService loggingService)

Method Detail

channelAdded

public void channelAdded(MigratableHandler readHandler,
                         MigratableHandler writeHandler)

channelRemoved

public void channelRemoved(MigratableHandler readHandler,
                           MigratableHandler writeHandler)

start

public void start()

stop

public void stop()

signalMigrationComplete

public void signalMigrationComplete()