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<pre><span class="sourceLineNo">001</span>/*<a name="line.1"></a>
<span class="sourceLineNo">002</span> * Licensed to the Apache Software Foundation (ASF) under one<a name="line.2"></a>
<span class="sourceLineNo">003</span> * or more contributor license agreements. See the NOTICE file<a name="line.3"></a>
<span class="sourceLineNo">004</span> * distributed with this work for additional information<a name="line.4"></a>
<span class="sourceLineNo">005</span> * regarding copyright ownership. The ASF licenses this file<a name="line.5"></a>
<span class="sourceLineNo">006</span> * to you under the Apache License, Version 2.0 (the<a name="line.6"></a>
<span class="sourceLineNo">007</span> * "License"); you may not use this file except in compliance<a name="line.7"></a>
<span class="sourceLineNo">008</span> * with the License. You may obtain a copy of the License at<a name="line.8"></a>
<span class="sourceLineNo">009</span> *<a name="line.9"></a>
<span class="sourceLineNo">010</span> * http://www.apache.org/licenses/LICENSE-2.0<a name="line.10"></a>
<span class="sourceLineNo">011</span> *<a name="line.11"></a>
<span class="sourceLineNo">012</span> * Unless required by applicable law or agreed to in writing, software<a name="line.12"></a>
<span class="sourceLineNo">013</span> * distributed under the License is distributed on an "AS IS" BASIS,<a name="line.13"></a>
<span class="sourceLineNo">014</span> * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.<a name="line.14"></a>
<span class="sourceLineNo">015</span> * See the License for the specific language governing permissions and<a name="line.15"></a>
<span class="sourceLineNo">016</span> * limitations under the License.<a name="line.16"></a>
<span class="sourceLineNo">017</span> */<a name="line.17"></a>
<span class="sourceLineNo">018</span>package org.apache.hadoop.hbase.ipc;<a name="line.18"></a>
<span class="sourceLineNo">019</span><a name="line.19"></a>
<span class="sourceLineNo">020</span>import java.util.Collection;<a name="line.20"></a>
<span class="sourceLineNo">021</span>import java.util.Iterator;<a name="line.21"></a>
<span class="sourceLineNo">022</span>import java.util.concurrent.BlockingQueue;<a name="line.22"></a>
<span class="sourceLineNo">023</span>import java.util.concurrent.LinkedBlockingDeque;<a name="line.23"></a>
<span class="sourceLineNo">024</span>import java.util.concurrent.LinkedBlockingQueue;<a name="line.24"></a>
<span class="sourceLineNo">025</span>import java.util.concurrent.TimeUnit;<a name="line.25"></a>
<span class="sourceLineNo">026</span>import java.util.concurrent.atomic.AtomicBoolean;<a name="line.26"></a>
<span class="sourceLineNo">027</span>import java.util.concurrent.atomic.LongAdder;<a name="line.27"></a>
<span class="sourceLineNo">028</span>import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;<a name="line.28"></a>
<span class="sourceLineNo">029</span>import org.apache.yetus.audience.InterfaceAudience;<a name="line.29"></a>
<span class="sourceLineNo">030</span><a name="line.30"></a>
<span class="sourceLineNo">031</span>/**<a name="line.31"></a>
<span class="sourceLineNo">032</span> * Adaptive LIFO blocking queue utilizing CoDel algorithm to prevent queue overloading. Implementing<a name="line.32"></a>
<span class="sourceLineNo">033</span> * {@link BlockingQueue} interface to be compatible with {@link RpcExecutor}. Currently uses<a name="line.33"></a>
<span class="sourceLineNo">034</span> * milliseconds internally, need to look into whether we should use nanoseconds for timeInterval and<a name="line.34"></a>
<span class="sourceLineNo">035</span> * minDelay.<a name="line.35"></a>
<span class="sourceLineNo">036</span> * @see &lt;a href="http://queue.acm.org/detail.cfm?id=2839461"&gt;Fail at Scale paper&lt;/a&gt;<a name="line.36"></a>
<span class="sourceLineNo">037</span> * @see &lt;a href="https://github.com/facebook/wangle/blob/master/wangle/concurrent/Codel.cpp"&gt; CoDel<a name="line.37"></a>
<span class="sourceLineNo">038</span> * version for generic job queues in Wangle library&lt;/a&gt;<a name="line.38"></a>
<span class="sourceLineNo">039</span> */<a name="line.39"></a>
<span class="sourceLineNo">040</span>@InterfaceAudience.Private<a name="line.40"></a>
<span class="sourceLineNo">041</span>public class AdaptiveLifoCoDelCallQueue implements BlockingQueue&lt;CallRunner&gt; {<a name="line.41"></a>
<span class="sourceLineNo">042</span><a name="line.42"></a>
<span class="sourceLineNo">043</span> // backing queue<a name="line.43"></a>
<span class="sourceLineNo">044</span> private LinkedBlockingDeque&lt;CallRunner&gt; queue;<a name="line.44"></a>
<span class="sourceLineNo">045</span><a name="line.45"></a>
<span class="sourceLineNo">046</span> // so we can calculate actual threshold to switch to LIFO under load<a name="line.46"></a>
<span class="sourceLineNo">047</span> private int maxCapacity;<a name="line.47"></a>
<span class="sourceLineNo">048</span><a name="line.48"></a>
<span class="sourceLineNo">049</span> // metrics (shared across all queues)<a name="line.49"></a>
<span class="sourceLineNo">050</span> private LongAdder numGeneralCallsDropped;<a name="line.50"></a>
<span class="sourceLineNo">051</span> private LongAdder numLifoModeSwitches;<a name="line.51"></a>
<span class="sourceLineNo">052</span><a name="line.52"></a>
<span class="sourceLineNo">053</span> // Both are in milliseconds<a name="line.53"></a>
<span class="sourceLineNo">054</span> private volatile int codelTargetDelay;<a name="line.54"></a>
<span class="sourceLineNo">055</span> private volatile int codelInterval;<a name="line.55"></a>
<span class="sourceLineNo">056</span><a name="line.56"></a>
<span class="sourceLineNo">057</span> // if queue if full more than that percent, we switch to LIFO mode.<a name="line.57"></a>
<span class="sourceLineNo">058</span> // Values are in the range of 0.7, 0.8 etc (0-1.0).<a name="line.58"></a>
<span class="sourceLineNo">059</span> private volatile double lifoThreshold;<a name="line.59"></a>
<span class="sourceLineNo">060</span><a name="line.60"></a>
<span class="sourceLineNo">061</span> // minimal delay observed during the interval<a name="line.61"></a>
<span class="sourceLineNo">062</span> private volatile long minDelay;<a name="line.62"></a>
<span class="sourceLineNo">063</span><a name="line.63"></a>
<span class="sourceLineNo">064</span> // the moment when current interval ends<a name="line.64"></a>
<span class="sourceLineNo">065</span> private volatile long intervalTime = EnvironmentEdgeManager.currentTime();<a name="line.65"></a>
<span class="sourceLineNo">066</span><a name="line.66"></a>
<span class="sourceLineNo">067</span> // switch to ensure only one threads does interval cutoffs<a name="line.67"></a>
<span class="sourceLineNo">068</span> private AtomicBoolean resetDelay = new AtomicBoolean(true);<a name="line.68"></a>
<span class="sourceLineNo">069</span><a name="line.69"></a>
<span class="sourceLineNo">070</span> // if we're in this mode, "long" calls are getting dropped<a name="line.70"></a>
<span class="sourceLineNo">071</span> private AtomicBoolean isOverloaded = new AtomicBoolean(false);<a name="line.71"></a>
<span class="sourceLineNo">072</span><a name="line.72"></a>
<span class="sourceLineNo">073</span> public AdaptiveLifoCoDelCallQueue(int capacity, int targetDelay, int interval,<a name="line.73"></a>
<span class="sourceLineNo">074</span> double lifoThreshold, LongAdder numGeneralCallsDropped, LongAdder numLifoModeSwitches) {<a name="line.74"></a>
<span class="sourceLineNo">075</span> this.maxCapacity = capacity;<a name="line.75"></a>
<span class="sourceLineNo">076</span> this.queue = new LinkedBlockingDeque&lt;&gt;(capacity);<a name="line.76"></a>
<span class="sourceLineNo">077</span> this.codelTargetDelay = targetDelay;<a name="line.77"></a>
<span class="sourceLineNo">078</span> this.codelInterval = interval;<a name="line.78"></a>
<span class="sourceLineNo">079</span> this.lifoThreshold = lifoThreshold;<a name="line.79"></a>
<span class="sourceLineNo">080</span> this.numGeneralCallsDropped = numGeneralCallsDropped;<a name="line.80"></a>
<span class="sourceLineNo">081</span> this.numLifoModeSwitches = numLifoModeSwitches;<a name="line.81"></a>
<span class="sourceLineNo">082</span> }<a name="line.82"></a>
<span class="sourceLineNo">083</span><a name="line.83"></a>
<span class="sourceLineNo">084</span> /**<a name="line.84"></a>
<span class="sourceLineNo">085</span> * Update tunables.<a name="line.85"></a>
<span class="sourceLineNo">086</span> * @param newCodelTargetDelay new CoDel target delay<a name="line.86"></a>
<span class="sourceLineNo">087</span> * @param newCodelInterval new CoDel interval<a name="line.87"></a>
<span class="sourceLineNo">088</span> * @param newLifoThreshold new Adaptive Lifo threshold<a name="line.88"></a>
<span class="sourceLineNo">089</span> */<a name="line.89"></a>
<span class="sourceLineNo">090</span> public void updateTunables(int newCodelTargetDelay, int newCodelInterval,<a name="line.90"></a>
<span class="sourceLineNo">091</span> double newLifoThreshold) {<a name="line.91"></a>
<span class="sourceLineNo">092</span> this.codelTargetDelay = newCodelTargetDelay;<a name="line.92"></a>
<span class="sourceLineNo">093</span> this.codelInterval = newCodelInterval;<a name="line.93"></a>
<span class="sourceLineNo">094</span> this.lifoThreshold = newLifoThreshold;<a name="line.94"></a>
<span class="sourceLineNo">095</span> }<a name="line.95"></a>
<span class="sourceLineNo">096</span><a name="line.96"></a>
<span class="sourceLineNo">097</span> /**<a name="line.97"></a>
<span class="sourceLineNo">098</span> * Behaves as {@link LinkedBlockingQueue#take()}, except it will silently skip all calls which it<a name="line.98"></a>
<span class="sourceLineNo">099</span> * thinks should be dropped.<a name="line.99"></a>
<span class="sourceLineNo">100</span> * @return the head of this queue<a name="line.100"></a>
<span class="sourceLineNo">101</span> * @throws InterruptedException if interrupted while waiting<a name="line.101"></a>
<span class="sourceLineNo">102</span> */<a name="line.102"></a>
<span class="sourceLineNo">103</span> @Override<a name="line.103"></a>
<span class="sourceLineNo">104</span> public CallRunner take() throws InterruptedException {<a name="line.104"></a>
<span class="sourceLineNo">105</span> CallRunner cr;<a name="line.105"></a>
<span class="sourceLineNo">106</span> while (true) {<a name="line.106"></a>
<span class="sourceLineNo">107</span> if (((double) queue.size() / this.maxCapacity) &gt; lifoThreshold) {<a name="line.107"></a>
<span class="sourceLineNo">108</span> numLifoModeSwitches.increment();<a name="line.108"></a>
<span class="sourceLineNo">109</span> cr = queue.takeLast();<a name="line.109"></a>
<span class="sourceLineNo">110</span> } else {<a name="line.110"></a>
<span class="sourceLineNo">111</span> cr = queue.takeFirst();<a name="line.111"></a>
<span class="sourceLineNo">112</span> }<a name="line.112"></a>
<span class="sourceLineNo">113</span> if (needToDrop(cr)) {<a name="line.113"></a>
<span class="sourceLineNo">114</span> numGeneralCallsDropped.increment();<a name="line.114"></a>
<span class="sourceLineNo">115</span> cr.drop();<a name="line.115"></a>
<span class="sourceLineNo">116</span> } else {<a name="line.116"></a>
<span class="sourceLineNo">117</span> return cr;<a name="line.117"></a>
<span class="sourceLineNo">118</span> }<a name="line.118"></a>
<span class="sourceLineNo">119</span> }<a name="line.119"></a>
<span class="sourceLineNo">120</span> }<a name="line.120"></a>
<span class="sourceLineNo">121</span><a name="line.121"></a>
<span class="sourceLineNo">122</span> @Override<a name="line.122"></a>
<span class="sourceLineNo">123</span> public CallRunner poll() {<a name="line.123"></a>
<span class="sourceLineNo">124</span> CallRunner cr;<a name="line.124"></a>
<span class="sourceLineNo">125</span> boolean switched = false;<a name="line.125"></a>
<span class="sourceLineNo">126</span> while (true) {<a name="line.126"></a>
<span class="sourceLineNo">127</span> if (((double) queue.size() / this.maxCapacity) &gt; lifoThreshold) {<a name="line.127"></a>
<span class="sourceLineNo">128</span> // Only count once per switch.<a name="line.128"></a>
<span class="sourceLineNo">129</span> if (!switched) {<a name="line.129"></a>
<span class="sourceLineNo">130</span> switched = true;<a name="line.130"></a>
<span class="sourceLineNo">131</span> numLifoModeSwitches.increment();<a name="line.131"></a>
<span class="sourceLineNo">132</span> }<a name="line.132"></a>
<span class="sourceLineNo">133</span> cr = queue.pollLast();<a name="line.133"></a>
<span class="sourceLineNo">134</span> } else {<a name="line.134"></a>
<span class="sourceLineNo">135</span> switched = false;<a name="line.135"></a>
<span class="sourceLineNo">136</span> cr = queue.pollFirst();<a name="line.136"></a>
<span class="sourceLineNo">137</span> }<a name="line.137"></a>
<span class="sourceLineNo">138</span> if (cr == null) {<a name="line.138"></a>
<span class="sourceLineNo">139</span> return cr;<a name="line.139"></a>
<span class="sourceLineNo">140</span> }<a name="line.140"></a>
<span class="sourceLineNo">141</span> if (needToDrop(cr)) {<a name="line.141"></a>
<span class="sourceLineNo">142</span> numGeneralCallsDropped.increment();<a name="line.142"></a>
<span class="sourceLineNo">143</span> cr.drop();<a name="line.143"></a>
<span class="sourceLineNo">144</span> } else {<a name="line.144"></a>
<span class="sourceLineNo">145</span> return cr;<a name="line.145"></a>
<span class="sourceLineNo">146</span> }<a name="line.146"></a>
<span class="sourceLineNo">147</span> }<a name="line.147"></a>
<span class="sourceLineNo">148</span> }<a name="line.148"></a>
<span class="sourceLineNo">149</span><a name="line.149"></a>
<span class="sourceLineNo">150</span> /**<a name="line.150"></a>
<span class="sourceLineNo">151</span> * @param callRunner to validate<a name="line.151"></a>
<span class="sourceLineNo">152</span> * @return true if this call needs to be skipped based on call timestamp and internal queue state<a name="line.152"></a>
<span class="sourceLineNo">153</span> * (deemed overloaded).<a name="line.153"></a>
<span class="sourceLineNo">154</span> */<a name="line.154"></a>
<span class="sourceLineNo">155</span> private boolean needToDrop(CallRunner callRunner) {<a name="line.155"></a>
<span class="sourceLineNo">156</span> long now = EnvironmentEdgeManager.currentTime();<a name="line.156"></a>
<span class="sourceLineNo">157</span> long callDelay = now - callRunner.getRpcCall().getReceiveTime();<a name="line.157"></a>
<span class="sourceLineNo">158</span><a name="line.158"></a>
<span class="sourceLineNo">159</span> long localMinDelay = this.minDelay;<a name="line.159"></a>
<span class="sourceLineNo">160</span><a name="line.160"></a>
<span class="sourceLineNo">161</span> // Try and determine if we should reset<a name="line.161"></a>
<span class="sourceLineNo">162</span> // the delay time and determine overload<a name="line.162"></a>
<span class="sourceLineNo">163</span> if (now &gt; intervalTime &amp;&amp; !resetDelay.get() &amp;&amp; !resetDelay.getAndSet(true)) {<a name="line.163"></a>
<span class="sourceLineNo">164</span> intervalTime = now + codelInterval;<a name="line.164"></a>
<span class="sourceLineNo">165</span><a name="line.165"></a>
<span class="sourceLineNo">166</span> isOverloaded.set(localMinDelay &gt; codelTargetDelay);<a name="line.166"></a>
<span class="sourceLineNo">167</span> }<a name="line.167"></a>
<span class="sourceLineNo">168</span><a name="line.168"></a>
<span class="sourceLineNo">169</span> // If it looks like we should reset the delay<a name="line.169"></a>
<span class="sourceLineNo">170</span> // time do it only once on one thread<a name="line.170"></a>
<span class="sourceLineNo">171</span> if (resetDelay.get() &amp;&amp; resetDelay.getAndSet(false)) {<a name="line.171"></a>
<span class="sourceLineNo">172</span> minDelay = callDelay;<a name="line.172"></a>
<span class="sourceLineNo">173</span> // we just reset the delay dunno about how this will work<a name="line.173"></a>
<span class="sourceLineNo">174</span> return false;<a name="line.174"></a>
<span class="sourceLineNo">175</span> } else if (callDelay &lt; localMinDelay) {<a name="line.175"></a>
<span class="sourceLineNo">176</span> minDelay = callDelay;<a name="line.176"></a>
<span class="sourceLineNo">177</span> }<a name="line.177"></a>
<span class="sourceLineNo">178</span><a name="line.178"></a>
<span class="sourceLineNo">179</span> return isOverloaded.get() &amp;&amp; callDelay &gt; 2 * codelTargetDelay;<a name="line.179"></a>
<span class="sourceLineNo">180</span> }<a name="line.180"></a>
<span class="sourceLineNo">181</span><a name="line.181"></a>
<span class="sourceLineNo">182</span> // Generic BlockingQueue methods we support<a name="line.182"></a>
<span class="sourceLineNo">183</span> @Override<a name="line.183"></a>
<span class="sourceLineNo">184</span> public boolean offer(CallRunner callRunner) {<a name="line.184"></a>
<span class="sourceLineNo">185</span> return queue.offer(callRunner);<a name="line.185"></a>
<span class="sourceLineNo">186</span> }<a name="line.186"></a>
<span class="sourceLineNo">187</span><a name="line.187"></a>
<span class="sourceLineNo">188</span> @Override<a name="line.188"></a>
<span class="sourceLineNo">189</span> public int size() {<a name="line.189"></a>
<span class="sourceLineNo">190</span> return queue.size();<a name="line.190"></a>
<span class="sourceLineNo">191</span> }<a name="line.191"></a>
<span class="sourceLineNo">192</span><a name="line.192"></a>
<span class="sourceLineNo">193</span> @Override<a name="line.193"></a>
<span class="sourceLineNo">194</span> public String toString() {<a name="line.194"></a>
<span class="sourceLineNo">195</span> return queue.toString();<a name="line.195"></a>
<span class="sourceLineNo">196</span> }<a name="line.196"></a>
<span class="sourceLineNo">197</span><a name="line.197"></a>
<span class="sourceLineNo">198</span> // This class does NOT provide generic purpose BlockingQueue implementation,<a name="line.198"></a>
<span class="sourceLineNo">199</span> // so to prevent misuse all other methods throw UnsupportedOperationException.<a name="line.199"></a>
<span class="sourceLineNo">200</span><a name="line.200"></a>
<span class="sourceLineNo">201</span> @Override<a name="line.201"></a>
<span class="sourceLineNo">202</span> public CallRunner poll(long timeout, TimeUnit unit) throws InterruptedException {<a name="line.202"></a>
<span class="sourceLineNo">203</span> throw new UnsupportedOperationException(<a name="line.203"></a>
<span class="sourceLineNo">204</span> "This class doesn't support anything," + " but take() and offer() methods");<a name="line.204"></a>
<span class="sourceLineNo">205</span> }<a name="line.205"></a>
<span class="sourceLineNo">206</span><a name="line.206"></a>
<span class="sourceLineNo">207</span> @Override<a name="line.207"></a>
<span class="sourceLineNo">208</span> public CallRunner peek() {<a name="line.208"></a>
<span class="sourceLineNo">209</span> throw new UnsupportedOperationException(<a name="line.209"></a>
<span class="sourceLineNo">210</span> "This class doesn't support anything," + " but take() and offer() methods");<a name="line.210"></a>
<span class="sourceLineNo">211</span> }<a name="line.211"></a>
<span class="sourceLineNo">212</span><a name="line.212"></a>
<span class="sourceLineNo">213</span> @Override<a name="line.213"></a>
<span class="sourceLineNo">214</span> public boolean remove(Object o) {<a name="line.214"></a>
<span class="sourceLineNo">215</span> throw new UnsupportedOperationException(<a name="line.215"></a>
<span class="sourceLineNo">216</span> "This class doesn't support anything," + " but take() and offer() methods");<a name="line.216"></a>
<span class="sourceLineNo">217</span> }<a name="line.217"></a>
<span class="sourceLineNo">218</span><a name="line.218"></a>
<span class="sourceLineNo">219</span> @Override<a name="line.219"></a>
<span class="sourceLineNo">220</span> public boolean contains(Object o) {<a name="line.220"></a>
<span class="sourceLineNo">221</span> throw new UnsupportedOperationException(<a name="line.221"></a>
<span class="sourceLineNo">222</span> "This class doesn't support anything," + " but take() and offer() methods");<a name="line.222"></a>
<span class="sourceLineNo">223</span> }<a name="line.223"></a>
<span class="sourceLineNo">224</span><a name="line.224"></a>
<span class="sourceLineNo">225</span> @Override<a name="line.225"></a>
<span class="sourceLineNo">226</span> public Object[] toArray() {<a name="line.226"></a>
<span class="sourceLineNo">227</span> throw new UnsupportedOperationException(<a name="line.227"></a>
<span class="sourceLineNo">228</span> "This class doesn't support anything," + " but take() and offer() methods");<a name="line.228"></a>
<span class="sourceLineNo">229</span> }<a name="line.229"></a>
<span class="sourceLineNo">230</span><a name="line.230"></a>
<span class="sourceLineNo">231</span> @Override<a name="line.231"></a>
<span class="sourceLineNo">232</span> public &lt;T&gt; T[] toArray(T[] a) {<a name="line.232"></a>
<span class="sourceLineNo">233</span> throw new UnsupportedOperationException(<a name="line.233"></a>
<span class="sourceLineNo">234</span> "This class doesn't support anything," + " but take() and offer() methods");<a name="line.234"></a>
<span class="sourceLineNo">235</span> }<a name="line.235"></a>
<span class="sourceLineNo">236</span><a name="line.236"></a>
<span class="sourceLineNo">237</span> @Override<a name="line.237"></a>
<span class="sourceLineNo">238</span> public void clear() {<a name="line.238"></a>
<span class="sourceLineNo">239</span> throw new UnsupportedOperationException(<a name="line.239"></a>
<span class="sourceLineNo">240</span> "This class doesn't support anything," + " but take() and offer() methods");<a name="line.240"></a>
<span class="sourceLineNo">241</span> }<a name="line.241"></a>
<span class="sourceLineNo">242</span><a name="line.242"></a>
<span class="sourceLineNo">243</span> @Override<a name="line.243"></a>
<span class="sourceLineNo">244</span> public int drainTo(Collection&lt;? super CallRunner&gt; c) {<a name="line.244"></a>
<span class="sourceLineNo">245</span> throw new UnsupportedOperationException(<a name="line.245"></a>
<span class="sourceLineNo">246</span> "This class doesn't support anything," + " but take() and offer() methods");<a name="line.246"></a>
<span class="sourceLineNo">247</span> }<a name="line.247"></a>
<span class="sourceLineNo">248</span><a name="line.248"></a>
<span class="sourceLineNo">249</span> @Override<a name="line.249"></a>
<span class="sourceLineNo">250</span> public int drainTo(Collection&lt;? super CallRunner&gt; c, int maxElements) {<a name="line.250"></a>
<span class="sourceLineNo">251</span> throw new UnsupportedOperationException(<a name="line.251"></a>
<span class="sourceLineNo">252</span> "This class doesn't support anything," + " but take() and offer() methods");<a name="line.252"></a>
<span class="sourceLineNo">253</span> }<a name="line.253"></a>
<span class="sourceLineNo">254</span><a name="line.254"></a>
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<span class="sourceLineNo">327</span>}<a name="line.327"></a>
</pre>
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