com.bigdata.util.concurrent

Class ThreadPoolExecutorStatisticsTask

java.lang.Object

com.bigdata.util.concurrent.ThreadPoolExecutorStatisticsTask

All Implemented Interfaces:

Runnable

public class ThreadPoolExecutorStatisticsTask
extends Object
implements Runnable

Class tracks a variety of information about a ThreadPoolExecutor including the moving average of its queue length, queuing times, etc.

Version:

$Id$

Author:

Bryan Thompson

Field Summary

Fields

Modifier and Type	Field and Description
static double	DEFAULT_WEIGHT The recommended default weight.

Constructor Summary

Constructors

Constructor and Description
ThreadPoolExecutorStatisticsTask(String serviceName, ThreadPoolExecutor service) Ctor variant when the ThreadPoolExecutor does not have hooks for an AbstractTask and therefore does not update TaskCounterss.
ThreadPoolExecutorStatisticsTask(String serviceName, ThreadPoolExecutor service, TaskCounters taskCounters) Ctor variant when the ThreadPoolExecutor has hooks for an AbstractTask and updates the given TaskCounterss.
ThreadPoolExecutorStatisticsTask(String serviceName, ThreadPoolExecutor service, TaskCounters taskCounters, double w) Core impl.

Method Summary

Methods

Modifier and Type	Method and Description
CounterSet	getCounters() Adds counters for all innate variables defined for a ThreadPoolExecutor and for each of the variables computed by this class.
double	getMovingAverage(double avg, double q, double w) Compute a moving average: (1 - w) * avg + w * q
long	getSampleCount() #of samples taken so far.
double	getWeight() The weight used to compute the moving average.
void	run() This should be invoked once per second to sample various counters in order to turn their values into moving averages.

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_WEIGHT

public static final double DEFAULT_WEIGHT

The recommended default weight.

See Also:

Constant Field Values

Constructor Detail

ThreadPoolExecutorStatisticsTask

public ThreadPoolExecutorStatisticsTask(String serviceName,
                                ThreadPoolExecutor service)

Ctor variant when the ThreadPoolExecutor does not have hooks for an AbstractTask and therefore does not update TaskCounterss.

Parameters:

serviceName - The label for the service.

service - The service to be monitored.

ThreadPoolExecutorStatisticsTask

public ThreadPoolExecutorStatisticsTask(String serviceName,
                                ThreadPoolExecutor service,
                                TaskCounters taskCounters)

Ctor variant when the ThreadPoolExecutor has hooks for an AbstractTask and updates the given TaskCounterss.

Parameters:

serviceName - The label for the service.

service - The service to be monitored.

taskCounters - The per-task counters used to compute the latency data for tasks run on that service.

ThreadPoolExecutorStatisticsTask

public ThreadPoolExecutorStatisticsTask(String serviceName,
                                ThreadPoolExecutor service,
                                TaskCounters taskCounters,
                                double w)

Core impl.

Parameters:

serviceName - The label for the service.

service - The service to be monitored.

taskCounters - The per-task counters used to compute the latency data for tasks run on that service.

w - The weight to be used by getMovingAverage(double, double, double)

Method Detail

getWeight

public double getWeight()

The weight used to compute the moving average.

getSampleCount

public long getSampleCount()

#of samples taken so far.

getMovingAverage

public double getMovingAverage(double avg,
                      double q,
                      double w)

Compute a moving average: (1 - w) * avg + w * q

Parameters:

avg - The previous average and initially zero (0.0).

q - The current value (e.g., the instantaneous measurement of the #of active tasks plus the length of the queue).

w - The weight for the moving average in (0:1). Values around .2 seem appropriate.

Returns:

The updated moving average.

run

public void run()

This should be invoked once per second to sample various counters in order to turn their values into moving averages.

Note: don't throw anything from here or it will cause the scheduled task executing this to no longer be run!

Specified by:

run in interface Runnable

getCounters

public CounterSet getCounters()

Adds counters for all innate variables defined for a ThreadPoolExecutor and for each of the variables computed by this class. Note that some variables (e.g., the lock waiting time) are only available when the service specified to the ctor is a WriteExecutorService.

Parameters:

counterSet - The counters will be added to this CounterSet.

Returns:

The caller's counterSet