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<pre><span class="source-line-no">001</span><span id="line-1">/*</span>
<span class="source-line-no">002</span><span id="line-2"> * Licensed to the Apache Software Foundation (ASF) under one</span>
<span class="source-line-no">003</span><span id="line-3"> * or more contributor license agreements. See the NOTICE file</span>
<span class="source-line-no">004</span><span id="line-4"> * distributed with this work for additional information</span>
<span class="source-line-no">005</span><span id="line-5"> * regarding copyright ownership. The ASF licenses this file</span>
<span class="source-line-no">006</span><span id="line-6"> * to you under the Apache License, Version 2.0 (the</span>
<span class="source-line-no">007</span><span id="line-7"> * "License"); you may not use this file except in compliance</span>
<span class="source-line-no">008</span><span id="line-8"> * with the License. You may obtain a copy of the License at</span>
<span class="source-line-no">009</span><span id="line-9"> *</span>
<span class="source-line-no">010</span><span id="line-10"> * http://www.apache.org/licenses/LICENSE-2.0</span>
<span class="source-line-no">011</span><span id="line-11"> *</span>
<span class="source-line-no">012</span><span id="line-12"> * Unless required by applicable law or agreed to in writing, software</span>
<span class="source-line-no">013</span><span id="line-13"> * distributed under the License is distributed on an "AS IS" BASIS,</span>
<span class="source-line-no">014</span><span id="line-14"> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.</span>
<span class="source-line-no">015</span><span id="line-15"> * See the License for the specific language governing permissions and</span>
<span class="source-line-no">016</span><span id="line-16"> * limitations under the License.</span>
<span class="source-line-no">017</span><span id="line-17"> */</span>
<span class="source-line-no">018</span><span id="line-18">package org.apache.hadoop.hbase.util;</span>
<span class="source-line-no">019</span><span id="line-19"></span>
<span class="source-line-no">020</span><span id="line-20">import java.lang.management.GarbageCollectorMXBean;</span>
<span class="source-line-no">021</span><span id="line-21">import java.lang.management.ManagementFactory;</span>
<span class="source-line-no">022</span><span id="line-22">import java.util.List;</span>
<span class="source-line-no">023</span><span id="line-23">import java.util.Map;</span>
<span class="source-line-no">024</span><span id="line-24">import java.util.Set;</span>
<span class="source-line-no">025</span><span id="line-25">import java.util.concurrent.TimeUnit;</span>
<span class="source-line-no">026</span><span id="line-26">import org.apache.hadoop.conf.Configuration;</span>
<span class="source-line-no">027</span><span id="line-27">import org.apache.hadoop.hbase.metrics.JvmPauseMonitorSource;</span>
<span class="source-line-no">028</span><span id="line-28">import org.apache.yetus.audience.InterfaceAudience;</span>
<span class="source-line-no">029</span><span id="line-29">import org.slf4j.Logger;</span>
<span class="source-line-no">030</span><span id="line-30">import org.slf4j.LoggerFactory;</span>
<span class="source-line-no">031</span><span id="line-31"></span>
<span class="source-line-no">032</span><span id="line-32">import org.apache.hbase.thirdparty.com.google.common.base.Joiner;</span>
<span class="source-line-no">033</span><span id="line-33">import org.apache.hbase.thirdparty.com.google.common.base.Preconditions;</span>
<span class="source-line-no">034</span><span id="line-34">import org.apache.hbase.thirdparty.com.google.common.base.Stopwatch;</span>
<span class="source-line-no">035</span><span id="line-35">import org.apache.hbase.thirdparty.com.google.common.collect.Lists;</span>
<span class="source-line-no">036</span><span id="line-36">import org.apache.hbase.thirdparty.com.google.common.collect.Maps;</span>
<span class="source-line-no">037</span><span id="line-37">import org.apache.hbase.thirdparty.com.google.common.collect.Sets;</span>
<span class="source-line-no">038</span><span id="line-38"></span>
<span class="source-line-no">039</span><span id="line-39">/**</span>
<span class="source-line-no">040</span><span id="line-40"> * Class which sets up a simple thread which runs in a loop sleeping for a short interval of time.</span>
<span class="source-line-no">041</span><span id="line-41"> * If the sleep takes significantly longer than its target time, it implies that the JVM or host</span>
<span class="source-line-no">042</span><span id="line-42"> * machine has paused processing, which may cause other problems. If such a pause is detected, the</span>
<span class="source-line-no">043</span><span id="line-43"> * thread logs a message. The original JvmPauseMonitor is:</span>
<span class="source-line-no">044</span><span id="line-44"> * ${hadoop-common-project}/hadoop-common/src/main/java/org/apache/hadoop/util/ JvmPauseMonitor.java</span>
<span class="source-line-no">045</span><span id="line-45"> * r1503806 | cmccabe | 2013-07-17 01:48:24 +0800 (Wed, 17 Jul 2013) | 1 line HADOOP-9618. thread</span>
<span class="source-line-no">046</span><span id="line-46"> * which detects GC pauses(Todd Lipcon)</span>
<span class="source-line-no">047</span><span id="line-47"> */</span>
<span class="source-line-no">048</span><span id="line-48">@InterfaceAudience.Private</span>
<span class="source-line-no">049</span><span id="line-49">public class JvmPauseMonitor {</span>
<span class="source-line-no">050</span><span id="line-50"> private static final Logger LOG = LoggerFactory.getLogger(JvmPauseMonitor.class);</span>
<span class="source-line-no">051</span><span id="line-51"></span>
<span class="source-line-no">052</span><span id="line-52"> /** The target sleep time */</span>
<span class="source-line-no">053</span><span id="line-53"> private static final long SLEEP_INTERVAL_MS = 500;</span>
<span class="source-line-no">054</span><span id="line-54"></span>
<span class="source-line-no">055</span><span id="line-55"> /** log WARN if we detect a pause longer than this threshold */</span>
<span class="source-line-no">056</span><span id="line-56"> private final long warnThresholdMs;</span>
<span class="source-line-no">057</span><span id="line-57"> public static final String WARN_THRESHOLD_KEY = "jvm.pause.warn-threshold.ms";</span>
<span class="source-line-no">058</span><span id="line-58"> private static final long WARN_THRESHOLD_DEFAULT = 10000;</span>
<span class="source-line-no">059</span><span id="line-59"></span>
<span class="source-line-no">060</span><span id="line-60"> /** log INFO if we detect a pause longer than this threshold */</span>
<span class="source-line-no">061</span><span id="line-61"> private final long infoThresholdMs;</span>
<span class="source-line-no">062</span><span id="line-62"> public static final String INFO_THRESHOLD_KEY = "jvm.pause.info-threshold.ms";</span>
<span class="source-line-no">063</span><span id="line-63"> private static final long INFO_THRESHOLD_DEFAULT = 1000;</span>
<span class="source-line-no">064</span><span id="line-64"></span>
<span class="source-line-no">065</span><span id="line-65"> private Thread monitorThread;</span>
<span class="source-line-no">066</span><span id="line-66"> private volatile boolean shouldRun = true;</span>
<span class="source-line-no">067</span><span id="line-67"> private JvmPauseMonitorSource metricsSource;</span>
<span class="source-line-no">068</span><span id="line-68"></span>
<span class="source-line-no">069</span><span id="line-69"> public JvmPauseMonitor(Configuration conf) {</span>
<span class="source-line-no">070</span><span id="line-70"> this(conf, null);</span>
<span class="source-line-no">071</span><span id="line-71"> }</span>
<span class="source-line-no">072</span><span id="line-72"></span>
<span class="source-line-no">073</span><span id="line-73"> public JvmPauseMonitor(Configuration conf, JvmPauseMonitorSource metricsSource) {</span>
<span class="source-line-no">074</span><span id="line-74"> this.warnThresholdMs = conf.getLong(WARN_THRESHOLD_KEY, WARN_THRESHOLD_DEFAULT);</span>
<span class="source-line-no">075</span><span id="line-75"> this.infoThresholdMs = conf.getLong(INFO_THRESHOLD_KEY, INFO_THRESHOLD_DEFAULT);</span>
<span class="source-line-no">076</span><span id="line-76"> this.metricsSource = metricsSource;</span>
<span class="source-line-no">077</span><span id="line-77"> }</span>
<span class="source-line-no">078</span><span id="line-78"></span>
<span class="source-line-no">079</span><span id="line-79"> public void start() {</span>
<span class="source-line-no">080</span><span id="line-80"> Preconditions.checkState(monitorThread == null, "Already started");</span>
<span class="source-line-no">081</span><span id="line-81"> monitorThread = new Thread(new Monitor(), "JvmPauseMonitor");</span>
<span class="source-line-no">082</span><span id="line-82"> monitorThread.setDaemon(true);</span>
<span class="source-line-no">083</span><span id="line-83"> monitorThread.start();</span>
<span class="source-line-no">084</span><span id="line-84"> }</span>
<span class="source-line-no">085</span><span id="line-85"></span>
<span class="source-line-no">086</span><span id="line-86"> public void stop() {</span>
<span class="source-line-no">087</span><span id="line-87"> shouldRun = false;</span>
<span class="source-line-no">088</span><span id="line-88"> monitorThread.interrupt();</span>
<span class="source-line-no">089</span><span id="line-89"> try {</span>
<span class="source-line-no">090</span><span id="line-90"> monitorThread.join();</span>
<span class="source-line-no">091</span><span id="line-91"> } catch (InterruptedException e) {</span>
<span class="source-line-no">092</span><span id="line-92"> Thread.currentThread().interrupt();</span>
<span class="source-line-no">093</span><span id="line-93"> }</span>
<span class="source-line-no">094</span><span id="line-94"> }</span>
<span class="source-line-no">095</span><span id="line-95"></span>
<span class="source-line-no">096</span><span id="line-96"> private String formatMessage(long extraSleepTime, List&lt;String&gt; gcDiffs) {</span>
<span class="source-line-no">097</span><span id="line-97"> String ret = "Detected pause in JVM or host machine (eg GC): " + "pause of approximately "</span>
<span class="source-line-no">098</span><span id="line-98"> + extraSleepTime + "ms\n";</span>
<span class="source-line-no">099</span><span id="line-99"> if (gcDiffs.isEmpty()) {</span>
<span class="source-line-no">100</span><span id="line-100"> ret += "No GCs detected";</span>
<span class="source-line-no">101</span><span id="line-101"> } else {</span>
<span class="source-line-no">102</span><span id="line-102"> ret += Joiner.on("\n").join(gcDiffs);</span>
<span class="source-line-no">103</span><span id="line-103"> }</span>
<span class="source-line-no">104</span><span id="line-104"> return ret;</span>
<span class="source-line-no">105</span><span id="line-105"> }</span>
<span class="source-line-no">106</span><span id="line-106"></span>
<span class="source-line-no">107</span><span id="line-107"> private Map&lt;String, GcTimes&gt; getGcTimes() {</span>
<span class="source-line-no">108</span><span id="line-108"> Map&lt;String, GcTimes&gt; map = Maps.newHashMap();</span>
<span class="source-line-no">109</span><span id="line-109"> List&lt;GarbageCollectorMXBean&gt; gcBeans = ManagementFactory.getGarbageCollectorMXBeans();</span>
<span class="source-line-no">110</span><span id="line-110"> for (GarbageCollectorMXBean gcBean : gcBeans) {</span>
<span class="source-line-no">111</span><span id="line-111"> map.put(gcBean.getName(), new GcTimes(gcBean));</span>
<span class="source-line-no">112</span><span id="line-112"> }</span>
<span class="source-line-no">113</span><span id="line-113"> return map;</span>
<span class="source-line-no">114</span><span id="line-114"> }</span>
<span class="source-line-no">115</span><span id="line-115"></span>
<span class="source-line-no">116</span><span id="line-116"> private static class GcTimes {</span>
<span class="source-line-no">117</span><span id="line-117"> private GcTimes(GarbageCollectorMXBean gcBean) {</span>
<span class="source-line-no">118</span><span id="line-118"> gcCount = gcBean.getCollectionCount();</span>
<span class="source-line-no">119</span><span id="line-119"> gcTimeMillis = gcBean.getCollectionTime();</span>
<span class="source-line-no">120</span><span id="line-120"> }</span>
<span class="source-line-no">121</span><span id="line-121"></span>
<span class="source-line-no">122</span><span id="line-122"> private GcTimes(long count, long time) {</span>
<span class="source-line-no">123</span><span id="line-123"> this.gcCount = count;</span>
<span class="source-line-no">124</span><span id="line-124"> this.gcTimeMillis = time;</span>
<span class="source-line-no">125</span><span id="line-125"> }</span>
<span class="source-line-no">126</span><span id="line-126"></span>
<span class="source-line-no">127</span><span id="line-127"> private GcTimes subtract(GcTimes other) {</span>
<span class="source-line-no">128</span><span id="line-128"> return new GcTimes(this.gcCount - other.gcCount, this.gcTimeMillis - other.gcTimeMillis);</span>
<span class="source-line-no">129</span><span id="line-129"> }</span>
<span class="source-line-no">130</span><span id="line-130"></span>
<span class="source-line-no">131</span><span id="line-131"> @Override</span>
<span class="source-line-no">132</span><span id="line-132"> public String toString() {</span>
<span class="source-line-no">133</span><span id="line-133"> return "count=" + gcCount + " time=" + gcTimeMillis + "ms";</span>
<span class="source-line-no">134</span><span id="line-134"> }</span>
<span class="source-line-no">135</span><span id="line-135"></span>
<span class="source-line-no">136</span><span id="line-136"> private long gcCount;</span>
<span class="source-line-no">137</span><span id="line-137"> private long gcTimeMillis;</span>
<span class="source-line-no">138</span><span id="line-138"> }</span>
<span class="source-line-no">139</span><span id="line-139"></span>
<span class="source-line-no">140</span><span id="line-140"> private class Monitor implements Runnable {</span>
<span class="source-line-no">141</span><span id="line-141"> @Override</span>
<span class="source-line-no">142</span><span id="line-142"> public void run() {</span>
<span class="source-line-no">143</span><span id="line-143"> Stopwatch sw = Stopwatch.createUnstarted();</span>
<span class="source-line-no">144</span><span id="line-144"> Map&lt;String, GcTimes&gt; gcTimesBeforeSleep = getGcTimes();</span>
<span class="source-line-no">145</span><span id="line-145"> while (shouldRun) {</span>
<span class="source-line-no">146</span><span id="line-146"> sw.reset().start();</span>
<span class="source-line-no">147</span><span id="line-147"> try {</span>
<span class="source-line-no">148</span><span id="line-148"> Thread.sleep(SLEEP_INTERVAL_MS);</span>
<span class="source-line-no">149</span><span id="line-149"> } catch (InterruptedException ie) {</span>
<span class="source-line-no">150</span><span id="line-150"> return;</span>
<span class="source-line-no">151</span><span id="line-151"> }</span>
<span class="source-line-no">152</span><span id="line-152"></span>
<span class="source-line-no">153</span><span id="line-153"> long extraSleepTime = sw.elapsed(TimeUnit.MILLISECONDS) - SLEEP_INTERVAL_MS;</span>
<span class="source-line-no">154</span><span id="line-154"> Map&lt;String, GcTimes&gt; gcTimesAfterSleep = getGcTimes();</span>
<span class="source-line-no">155</span><span id="line-155"></span>
<span class="source-line-no">156</span><span id="line-156"> if (extraSleepTime &gt; infoThresholdMs) {</span>
<span class="source-line-no">157</span><span id="line-157"> Set&lt;String&gt; gcBeanNames =</span>
<span class="source-line-no">158</span><span id="line-158"> Sets.intersection(gcTimesAfterSleep.keySet(), gcTimesBeforeSleep.keySet());</span>
<span class="source-line-no">159</span><span id="line-159"> List&lt;String&gt; gcDiffs = Lists.newArrayList();</span>
<span class="source-line-no">160</span><span id="line-160"> for (String name : gcBeanNames) {</span>
<span class="source-line-no">161</span><span id="line-161"> GcTimes diff = gcTimesAfterSleep.get(name).subtract(gcTimesBeforeSleep.get(name));</span>
<span class="source-line-no">162</span><span id="line-162"> if (diff.gcCount != 0) {</span>
<span class="source-line-no">163</span><span id="line-163"> gcDiffs.add("GC pool '" + name + "' had collection(s): " + diff.toString());</span>
<span class="source-line-no">164</span><span id="line-164"> }</span>
<span class="source-line-no">165</span><span id="line-165"> }</span>
<span class="source-line-no">166</span><span id="line-166"></span>
<span class="source-line-no">167</span><span id="line-167"> updateMetrics(extraSleepTime, !gcDiffs.isEmpty());</span>
<span class="source-line-no">168</span><span id="line-168"></span>
<span class="source-line-no">169</span><span id="line-169"> if (extraSleepTime &gt; warnThresholdMs) {</span>
<span class="source-line-no">170</span><span id="line-170"> LOG.warn(formatMessage(extraSleepTime, gcDiffs));</span>
<span class="source-line-no">171</span><span id="line-171"> } else {</span>
<span class="source-line-no">172</span><span id="line-172"> LOG.info(formatMessage(extraSleepTime, gcDiffs));</span>
<span class="source-line-no">173</span><span id="line-173"> }</span>
<span class="source-line-no">174</span><span id="line-174"> }</span>
<span class="source-line-no">175</span><span id="line-175"> gcTimesBeforeSleep = gcTimesAfterSleep;</span>
<span class="source-line-no">176</span><span id="line-176"> }</span>
<span class="source-line-no">177</span><span id="line-177"> }</span>
<span class="source-line-no">178</span><span id="line-178"> }</span>
<span class="source-line-no">179</span><span id="line-179"></span>
<span class="source-line-no">180</span><span id="line-180"> public void updateMetrics(long sleepTime, boolean gcDetected) {</span>
<span class="source-line-no">181</span><span id="line-181"> if (metricsSource != null) {</span>
<span class="source-line-no">182</span><span id="line-182"> if (sleepTime &gt; warnThresholdMs) {</span>
<span class="source-line-no">183</span><span id="line-183"> metricsSource.incWarnThresholdExceeded(1);</span>
<span class="source-line-no">184</span><span id="line-184"> } else {</span>
<span class="source-line-no">185</span><span id="line-185"> metricsSource.incInfoThresholdExceeded(1);</span>
<span class="source-line-no">186</span><span id="line-186"> }</span>
<span class="source-line-no">187</span><span id="line-187"> if (gcDetected) {</span>
<span class="source-line-no">188</span><span id="line-188"> metricsSource.updatePauseTimeWithGc(sleepTime);</span>
<span class="source-line-no">189</span><span id="line-189"> } else {</span>
<span class="source-line-no">190</span><span id="line-190"> metricsSource.updatePauseTimeWithoutGc(sleepTime);</span>
<span class="source-line-no">191</span><span id="line-191"> }</span>
<span class="source-line-no">192</span><span id="line-192"> }</span>
<span class="source-line-no">193</span><span id="line-193"> }</span>
<span class="source-line-no">194</span><span id="line-194"></span>
<span class="source-line-no">195</span><span id="line-195"> public JvmPauseMonitorSource getMetricsSource() {</span>
<span class="source-line-no">196</span><span id="line-196"> return metricsSource;</span>
<span class="source-line-no">197</span><span id="line-197"> }</span>
<span class="source-line-no">198</span><span id="line-198"></span>
<span class="source-line-no">199</span><span id="line-199"> public void setMetricsSource(JvmPauseMonitorSource metricsSource) {</span>
<span class="source-line-no">200</span><span id="line-200"> this.metricsSource = metricsSource;</span>
<span class="source-line-no">201</span><span id="line-201"> }</span>
<span class="source-line-no">202</span><span id="line-202"></span>
<span class="source-line-no">203</span><span id="line-203"> /**</span>
<span class="source-line-no">204</span><span id="line-204"> * Simple 'main' to facilitate manual testing of the pause monitor. This main function just leaks</span>
<span class="source-line-no">205</span><span id="line-205"> * memory into a list. Running this class with a 1GB heap will very quickly go into "GC hell" and</span>
<span class="source-line-no">206</span><span id="line-206"> * result in log messages about the GC pauses.</span>
<span class="source-line-no">207</span><span id="line-207"> */</span>
<span class="source-line-no">208</span><span id="line-208"> public static void main(String[] args) throws Exception {</span>
<span class="source-line-no">209</span><span id="line-209"> new JvmPauseMonitor(new Configuration()).start();</span>
<span class="source-line-no">210</span><span id="line-210"> List&lt;String&gt; list = Lists.newArrayList();</span>
<span class="source-line-no">211</span><span id="line-211"> int i = 0;</span>
<span class="source-line-no">212</span><span id="line-212"> while (true) {</span>
<span class="source-line-no">213</span><span id="line-213"> list.add(String.valueOf(i++));</span>
<span class="source-line-no">214</span><span id="line-214"> }</span>
<span class="source-line-no">215</span><span id="line-215"> }</span>
<span class="source-line-no">216</span><span id="line-216">}</span>
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