content: /*
   * Licensed to the Apache Software Foundation (ASF) under one or more
   * contributor license agreements. See the NOTICE file distributed with
   * this work for additional information regarding copyright ownership.
   * The ASF licenses this file to You 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 org.apache.activemq.artemis.tests.performance.jmh;
  
  import java.util.SplittableRandom;
  
  import org.apache.activemq.artemis.api.core.SimpleString;
  import org.apache.activemq.artemis.core.persistence.impl.nullpm.NullStorageManager;
  import org.apache.activemq.artemis.core.postoffice.DuplicateIDCache;
  import org.apache.activemq.artemis.core.postoffice.impl.DuplicateIDCaches;
  import org.apache.activemq.artemis.utils.RandomUtil;
  import org.openjdk.jmh.annotations.Benchmark;
  import org.openjdk.jmh.annotations.Fork;
  import org.openjdk.jmh.annotations.Measurement;
  import org.openjdk.jmh.annotations.Param;
  import org.openjdk.jmh.annotations.Scope;
  import org.openjdk.jmh.annotations.Setup;
  import org.openjdk.jmh.annotations.State;
  import org.openjdk.jmh.annotations.TearDown;
  import org.openjdk.jmh.annotations.Warmup;
  
  @State(Scope.Benchmark)
  @Fork(2)
  @Warmup(iterations = 5, time = 1)
  @Measurement(iterations = 8, time = 1)
  public class DuplicateIDCacheBenchmark {
  
     @Param({"20000"})
     private int size;
     @Param({"false", "true"})
     private boolean persist;
  
     private DuplicateIDCache cache;
  
     private byte[][] ids;
     private int idsMask;
     private int missingIdsMask;
     private long nextId;
     private byte[][] randomEvictedIds;
  
     @Setup
     public void init() throws Exception {
        cache = persist ?
           DuplicateIDCaches.persistent(SimpleString.of("benchmark"), size, new NullStorageManager()) :
           DuplicateIDCaches.inMemory(SimpleString.of("benchmark"), size);
        final int idSize = findNextHigherPowerOf2(size);
        idsMask = idSize - 1;
        nextId = 0;
        ids = new byte[idSize][];
        // fill the cache
        for (int i = 0; i < size; i++) {
           final byte[] id = RandomUtil.randomBytes();
           ids[i] = id;
           cache.addToCache(id, null, true);
        }
        // evict the first (idSize - size) elements on the ids array.
        // Given that being a FIFO cache isn't a stable contract it's going to validate it too.
        final int evicted = idSize - size;
        for (int i = 0; i < evicted; i++) {
           final byte[] id = RandomUtil.randomBytes();
           ids[size + i] = id;
           cache.addToCache(id, null, true);
           // check correctness of eviction policy
           if (cache.contains(ids[i])) {
              throw new AssertionError("This cache isn't using anymore a FIFO eviction strategy or its real capacity is > " + size);
           }
        }
        // always use the same seed!
        SplittableRandom random = new SplittableRandom(0);
        // set it big enough to trick branch predictors
        final int evictedIdsLength = findNextPowerOf2(Math.max(1024, evicted));
        missingIdsMask = evictedIdsLength - 1;
        randomEvictedIds = new byte[evictedIdsLength][];
        for (int i = 0; i < evictedIdsLength; i++) {
           final int id = random.nextInt(0, evicted);
           randomEvictedIds[i] = ids[id];
           // check correctness of eviction policy
           if (cache.contains(ids[id])) {
              throw new AssertionError("This cache isn't using anymore a FIFO eviction strategy");
           }
        }
     }
  
     // it isn't checking what's the max power of 2 number nor if size > 0
     private static int findNextHigherPowerOf2(int size) {
        final int nextPow2 = findNextPowerOf2(size);
        if (nextPow2 > size) {
           return nextPow2;
        }
        return nextPow2 * 2;
     }
  
     private static int findNextPowerOf2(int size) {
        return 1 << (32 - Integer.numberOfLeadingZeros(size - 1));
     }
  
     private byte[] nextId() {
        final long seq = nextId;
        final int index = (int) (seq & idsMask);
        nextId = seq + 1;
        return ids[index];
     }
  
     private byte[] nextMissingId() {
        final long seq = nextId;
        final int index = (int) (seq & missingIdsMask);
        nextId = seq + 1;
        return randomEvictedIds[index];
     }
  
     @Benchmark
     public boolean atomicVerify() throws Exception {
        return cache.atomicVerify(nextId(), null);
     }
  
     @Benchmark
     public boolean containsMissingId() {
        return cache.contains(nextMissingId());
     }
  
     @TearDown
     public void clear() throws Exception {
        cache.clear();
     }
  
  }
  