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1   /**
2    * Copyright The Apache Software Foundation
3    *
4    * Licensed to the Apache Software Foundation (ASF) under one or more
5    * contributor license agreements. See the NOTICE file distributed with this
6    * work for additional information regarding copyright ownership. The ASF
7    * licenses this file to you under the Apache License, Version 2.0 (the
8    * "License"); you may not use this file except in compliance with the License.
9    * You may obtain a copy of the License at
10   *
11   * http://www.apache.org/licenses/LICENSE-2.0
12   *
13   * Unless required by applicable law or agreed to in writing, software
14   * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
15   * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
16   * License for the specific language governing permissions and limitations
17   * under the License.
18   */
19  package org.apache.hadoop.hbase.io.hfile.bucket;
20  
21  import java.util.concurrent.atomic.AtomicLong;
22  
23  import org.apache.hadoop.classification.InterfaceAudience;
24  import org.apache.hadoop.hbase.io.hfile.CacheStats;
25  import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
26  
27  /**
28   * Class that implements cache metrics for bucket cache.
29   */
30  @InterfaceAudience.Private
31  public class BucketCacheStats extends CacheStats {
32    private final AtomicLong ioHitCount = new AtomicLong(0);
33    private final AtomicLong ioHitTime = new AtomicLong(0);
34    private final static int nanoTime = 1000000;
35    private long lastLogTime = EnvironmentEdgeManager.currentTime();
36  
37    BucketCacheStats() {
38      super("BucketCache");
39    }
40  
41    @Override
42    public String toString() {
43      return super.toString() + ", ioHitsPerSecond=" + getIOHitsPerSecond() +
44        ", ioTimePerHit=" + getIOTimePerHit();
45    }
46  
47    public void ioHit(long time) {
48      ioHitCount.incrementAndGet();
49      ioHitTime.addAndGet(time);
50    }
51  
52    public long getIOHitsPerSecond() {
53      long now = EnvironmentEdgeManager.currentTime();
54      long took = (now - lastLogTime) / 1000;
55      lastLogTime = now;
56      return took == 0? 0: ioHitCount.get() / took;
57    }
58  
59    public double getIOTimePerHit() {
60      long time = ioHitTime.get() / nanoTime;
61      long count = ioHitCount.get();
62      return ((float) time / (float) count);
63    }
64  
65    public void reset() {
66      ioHitCount.set(0);
67      ioHitTime.set(0);
68    }
69  }