org.apache.hadoop.hdfs.util

Class DataTransferThrottler

java.lang.Object

org.apache.hadoop.hdfs.util.DataTransferThrottler

public class DataTransferThrottler
extends Object

a class to throttle the data transfers. This class is thread safe. It can be shared by multiple threads. The parameter bandwidthPerSec specifies the total bandwidth shared by threads.

Constructor Summary

Constructors

Constructor and Description
DataTransferThrottler(long bandwidthPerSec) Constructor
DataTransferThrottler(long period, long bandwidthPerSec) Constructor

Method Summary

Methods

Modifier and Type	Method and Description
long	getBandwidth()
void	setBandwidth(long bytesPerSecond) Sets throttle bandwidth.
void	throttle(long numOfBytes) Given the numOfBytes sent/received since last time throttle was called, make the current thread sleep if I/O rate is too fast compared to the given bandwidth.
void	throttle(long numOfBytes, org.apache.hadoop.hdfs.util.Canceler canceler) Given the numOfBytes sent/received since last time throttle was called, make the current thread sleep if I/O rate is too fast compared to the given bandwidth.

Methods inherited from class java.lang.Object

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

Constructor Detail

DataTransferThrottler

public DataTransferThrottler(long bandwidthPerSec)

Constructor

Parameters:

bandwidthPerSec - bandwidth allowed in bytes per second.

DataTransferThrottler

public DataTransferThrottler(long period,
                     long bandwidthPerSec)

Constructor

Parameters:

period - in milliseconds. Bandwidth is enforced over this period.

bandwidthPerSec - bandwidth allowed in bytes per second.

Method Detail

getBandwidth

public long getBandwidth()

Returns:

current throttle bandwidth in bytes per second.

setBandwidth

public void setBandwidth(long bytesPerSecond)

Sets throttle bandwidth. This takes affect latest by the end of current period.

throttle

public void throttle(long numOfBytes)

Given the numOfBytes sent/received since last time throttle was called, make the current thread sleep if I/O rate is too fast compared to the given bandwidth.

Parameters:

numOfBytes - number of bytes sent/received since last time throttle was called

throttle

public void throttle(long numOfBytes,
            org.apache.hadoop.hdfs.util.Canceler canceler)

Given the numOfBytes sent/received since last time throttle was called, make the current thread sleep if I/O rate is too fast compared to the given bandwidth. Allows for optional external cancelation.

Parameters:

numOfBytes - number of bytes sent/received since last time throttle was called

canceler - optional canceler to check for abort of throttle