Console and Eepsite Jetty:

Switch back to QueuedThreadPool (ticket #1395)
In Jetty 5/6, the default QTP was not concurrent, so we switched to
ThreadPoolExecutor with a fixed-size queue, a set maxThreads,
and a RejectedExecutionPolicy of CallerRuns.
Unfortunately, CallerRuns causes lockups in Jetty NIO.
In addition, no flavor of TPE gives us what QTP does:
- TPE direct handoff (which we were using) never queues.
  This doesn't provide any burst management when maxThreads is reached.
  CallerRuns was an attempt to work around that.
- TPE unbounded queue does not adjust the number of threads.
  This doesn't provide automatic resource management.
- TPE bounded queue does not add threads until the queue is full.
  This doesn't provide good responsiveness to even small bursts.
QTP adds threads as soon as the queue is non-empty.
QTP as of Jetty 7 uses concurrent.
QTP unbounded queue is the default in Jetty.
So switch back to QTP with a bounded queue, which does what we want,
which is first expand the thread pool, then start queueing, then reject.

ref:
http://docs.oracle.com/javase/6/docs/api/java/util/concurrent/ThreadPoolExecutor.html
https://wiki.eclipse.org/Jetty/Howto/High_Load

installer/resources/eepsite/jetty.xml

@@ -53,26 +53,50 @@
 
       <!-- PICK ONE -->
 
-      <!-- If you don't have or want threadpool
-           Requests above the max will be queued
+      <!--
+           Recommended.
+           Two threads are used for the Connector and Acceptor.
+           Concurrent requests above maxThreads + queue size - 2 will be rejected and logged.
+           Due to the way QTP works, queue size should be larger than maxThreads.
+           Increase all values for high-traffic eepsites.
+
+           ref:
+           https://wiki.eclipse.org/Jetty/Howto/High_Load
+           http://trac.i2p2.i2p/ticket/1395
        -->
-     <!--
       <New class="org.eclipse.jetty.util.thread.QueuedThreadPool">
-        <Set name="minThreads">1</Set>
-        <Set name="maxThreads">16</Set>
+        <Arg>
+           <New class="java.util.concurrent.LinkedBlockingQueue">
+              <Arg type="int">40</Arg>
+           </New>
+        </Arg>
+        <Set name="minThreads">3</Set>
+        <Set name="maxThreads">20</Set>
+        <Set name="maxIdleTimeMs">60000</Set>
+        <Set name="daemon">true</Set>
+        <Set name="name">Eepsite Jetty</Set>
       </New>
-     -->
 
       <!-- Optional Java 5 bounded threadpool with job queue 
            Requests above the max will be rejected and logged.
            High-traffic sites should increase maximumPoolSize.
+
+           Args are:
+             corePoolSize (should be at least 3)
+             maximumPoolSize
+             keepAliveTime (milliseconds)
+             timeout (TimeUnit)
+             queue (BlockingQueue)
+
+           Not recommended.
+           ref:
+           http://trac.i2p2.i2p/ticket/1395
+           http://docs.oracle.com/javase/6/docs/api/java/util/concurrent/ThreadPoolExecutor.html
        -->
+     <!--
       <New class="org.eclipse.jetty.util.thread.ExecutorThreadPool">
-        <!-- corePoolSize (should be at least 3) -->
         <Arg type="int">3</Arg>
-        <!-- maximumPoolSize -->
         <Arg type="int">20</Arg>
-        <!-- keepAliveTime (milliseconds) -->
         <Arg type="long">60000</Arg>
         <Arg>
             <Call class="java.util.concurrent.TimeUnit" name="valueOf" >
@@ -83,6 +107,7 @@
             <New class="java.util.concurrent.SynchronousQueue" />
         </Arg>
       </New>
+     -->
     </Set>