/*
* Copyright 2016 Ben Manes. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.github.benmanes.caffeine.cache.simulator.policy.product;
import static com.google.common.base.Preconditions.checkState;
import static java.util.stream.Collectors.toSet;
import java.io.IOException;
import java.io.UncheckedIOException;
import java.nio.ByteBuffer;
import java.util.HashSet;
import java.util.Set;
import org.caffinitas.ohc.CacheSerializer;
import org.caffinitas.ohc.Eviction;
import org.caffinitas.ohc.OHCache;
import org.caffinitas.ohc.OHCacheBuilder;
import com.github.benmanes.caffeine.cache.simulator.BasicSettings;
import com.github.benmanes.caffeine.cache.simulator.policy.Policy;
import com.github.benmanes.caffeine.cache.simulator.policy.PolicyStats;
import com.typesafe.config.Config;
/**
* Off-Heap-Cache implementation.
*
* @author ben.manes@gmail.com (Ben Manes)
*/
public final class OhcPolicy implements Policy {
private static final int ENTRY_SIZE = 80;
private final OHCache<Long, Long> cache;
private final PolicyStats policyStats;
public OhcPolicy(OhcSettings settings, Eviction policy) {
cache = OHCacheBuilder.<Long, Long>newBuilder()
.capacity(ENTRY_SIZE * settings.maximumSize())
.edenSize(settings.percentEden())
.valueSerializer(longSerializer)
.keySerializer(longSerializer)
.eviction(policy)
.build();
policyStats = new PolicyStats(String.format("product.OHC (%s)",
(policy == Eviction.LRU) ? "Lru" : "W-TinyLfu"));
}
/** Returns all variations of this policy based on the configuration parameters. */
public static Set<Policy> policies(Config config) {
OhcSettings settings = new OhcSettings(config);
return settings.policy().stream()
.map(policy -> new OhcPolicy(settings, policy))
.collect(toSet());
}
@Override
public void record(long key) {
Object value = cache.get(key);
if (value == null) {
cache.put(key, key);
policyStats.recordMiss();
} else {
policyStats.recordHit();
}
}
@Override
public PolicyStats stats() {
return policyStats;
}
@Override
public void finished() {
policyStats.addEvictions(cache.stats().getEvictionCount());
checkState(policyStats.hitCount() == cache.stats().getHitCount());
checkState(policyStats.missCount() == cache.stats().getMissCount());
try {
cache.close();
} catch (IOException e) {
throw new UncheckedIOException(e);
}
}
static final class OhcSettings extends BasicSettings {
public OhcSettings(Config config) {
super(config);
}
public double percentEden() {
return config().getDouble("ohc.percent-eden");
}
public Set<Eviction> policy() {
Set<Eviction> policies = new HashSet<>();
for (String policy : config().getStringList("ohc.policy")) {
String name = policy.toLowerCase().replaceAll("[^a-z]", "");
if (name.equals("lru")) {
policies.add(Eviction.LRU);
} else if (name.equals("wtinylfu")) {
policies.add(Eviction.W_TINY_LFU);
} else {
throw new IllegalArgumentException("Unknown policy: " + policy);
}
}
return policies;
}
}
static final CacheSerializer<Long> longSerializer = new CacheSerializer<Long>() {
@Override public void serialize(Long value, ByteBuffer buffer) {
buffer.putLong(value);
}
@Override public Long deserialize(ByteBuffer buffer) {
return buffer.getLong();
}
@Override public int serializedSize(Long value) {
return Long.BYTES;
}
};
}