com.github.benmanes.caffeine.cache.simulator.policy.irr

Class DClockPolicy

java.lang.Object

com.github.benmanes.caffeine.cache.simulator.policy.irr.DClockPolicy

All Implemented Interfaces:

Policy, Policy.KeyOnlyPolicy

public final class DClockPolicy
extends Object
implements Policy.KeyOnlyPolicy

Double Clock algorithm. This algorithm organizes blocks by their reuse distance and partitions the cache into an active and inactive space. A new arrival enters the inactive space and on a subsequent hit is promoted to the active space, which may cause the oldest active entry to be demoted to be inactive. An eviction discards the oldest inactive entry which becomes a shadow (non-resident) node and is stamped with its refault distance. If on a cache miss the shadow entry exists and has a refault distance that is less than the active space's size, then it is optimistically promoted on insert.

The algorithm is explained by the authors in linux/mm/workingset.c. The target size of the active and inactive list is calculated in linux/mm/vmscan.c.

Nested Class Summary

Nested classes/interfaces inherited from interface com.github.benmanes.caffeine.cache.simulator.policy.Policy

Policy.Characteristic, Policy.KeyOnlyPolicy, Policy.PolicySpec

Constructor Summary

Constructors

Constructor and Description
DClockPolicy(com.github.benmanes.caffeine.cache.simulator.policy.irr.DClockPolicy.DClockSettings settings, double percentActive)

Method Summary

Modifier and Type	Method and Description
void	finished() Indicates that the recording has completed.
static Set<Policy>	policies(Config config) Returns all variations of this policy based on the configuration parameters.
void	record(long key)
PolicyStats	stats() Returns the cache efficiency statistics.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.github.benmanes.caffeine.cache.simulator.policy.Policy.KeyOnlyPolicy

record

Methods inherited from interface com.github.benmanes.caffeine.cache.simulator.policy.Policy

name

Constructor Detail

DClockPolicy

public DClockPolicy(com.github.benmanes.caffeine.cache.simulator.policy.irr.DClockPolicy.DClockSettings settings,
                    double percentActive)

Method Detail

policies

public static Set<Policy> policies(Config config)

Returns all variations of this policy based on the configuration parameters.

record

public void record(long key)

Specified by:

record in interface Policy.KeyOnlyPolicy

stats

public PolicyStats stats()

Description copied from interface: Policy

Returns the cache efficiency statistics.

Specified by:

stats in interface Policy

finished

public void finished()

Description copied from interface: Policy

Indicates that the recording has completed.

Specified by:

finished in interface Policy