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

Class LirsPolicy

java.lang.Object

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

All Implemented Interfaces:

Policy

public final class LirsPolicy
extends Object
implements Policy

Low Inter-reference Recency Set (LIRS) algorithm. This algorithm organizes blocks by their inter-reference recency (IRR) and groups entries as either having a low (LIR) or high (HIR) recency. A LIR entry is preferable to retain in the cache and evicted HIR entries may be retained as non-resident HIR entries. This allows a non-resident HIR entry to be promoted to a LIR entry shortly after a cache miss. The authors recommend sizing the maximum number of LIR blocks to 99% of the cache's total size (1% remaining for HIR blocks).

The authors do not provide a recommendation for setting the maximum number of non-resident HIR blocks. To avoid unbounded memory usage, these blocks are placed on a non-resident queue to allow immediate removal, when a non-resident size limit is reached, instead of searching the stack.

The algorithm is explained by the authors in LIRS: An Efficient Low Inter-reference Recency Set Replacement Policy to Improve Buffer Cache Performance and Making LRU Friendly to Weak Locality Workloads: A Novel Replacement Algorithm to Improve Buffer Cache Performance.

Constructor Summary

Constructors

Constructor and Description
LirsPolicy(com.typesafe.config.Config config)

Method Summary

Modifier and Type	Method and Description
void	finished() Indicates that the recording has completed.
static Set<Policy>	policies(com.typesafe.config.Config config) Returns all variations of this policy based on the configuration parameters.
void	record(long key) Records that the entry was accessed.
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

Constructor Detail

LirsPolicy

public LirsPolicy(com.typesafe.config.Config config)

Method Detail

policies

public static Set<Policy> policies(com.typesafe.config.Config config)

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

record

public void record(long key)

Description copied from interface: Policy

Records that the entry was accessed.

Specified by:

record in interface Policy

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