Package noaa.coastwatch.io

Class CacheOptimizer

java.lang.Object

noaa.coastwatch.io.CacheOptimizer

public class CacheOptimizer
extends Object

The CacheOptimizer class is a helper for caches that monitors cache access and miss rates and optimizes the cache size. The algorithm tries to maintain the cache miss rate (ie: page fault rate) within an acceptable window specified by the caller.

Since:

3.8.1

Author:

Peter Hollemans

Constructor Summary

Constructors

Constructor	Description
CacheOptimizer(double minMissRate, double maxMissRate, Runnable growTask, Runnable shrinkTask)	Creates a new cache optimizer.

Method Summary

Modifier and Type	Method	Description
void	access()	Signals that the cache had an access (either hit or miss).
void	miss()	Signals that the cache had a miss.
static long	timeOperation(Runnable operation)	Times the execution of an operation that uses the cache to nanosecond precision.

Methods inherited from class java.lang.Object

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

Constructor Details

CacheOptimizer

public CacheOptimizer(double minMissRate,
 double maxMissRate,
 Runnable growTask,
 Runnable shrinkTask)

Creates a new cache optimizer.

Parameters:

minMissRate - the minimum desired cache miss rate in the range [0..1].

maxMissRate - the maximum desired cache miss rate in the range [0..1].

growTask - the runnable to call to grow the cache size.

shrinkTask - the runnable to call to shrink the cache size.

Method Details

timeOperation

public static long timeOperation(Runnable operation)

Times the execution of an operation that uses the cache to nanosecond precision.

Parameters:

operation - the operation to time.

Returns:

the operation time in nanoseconds (ns).

access

public void access()

Signals that the cache had an access (either hit or miss).

miss

public void miss()

Signals that the cache had a miss.