Home

Welcome to the jeromq wiki!

Guide

Please read the bible first.

JeroMQ ported guide examples.

Cautions

• Context.term() must be called before interrupting a thread by Thread.interrupt. Otherwise internal pipe which is used to signal ZMQ commands will be shutdown unexpectedly.
• [Sharing ZContext] (https://github.com/zeromq/jeromq/wiki/Sharing-ZContext-between-thread)

Common mistakes (Already mentioned at the zguide )

• Close all the sockets properly otherwise Context.term() will wait forever
• Set a proper linger by using Socket.setLinger(millis) when you want to wait before socket termination. Otherwise some last messages could not be delivered.
• Set a propert HWM (High Water Mark). At 0MQ 3.x, you should set Socket.setSndHWM and setRcvHWM separately. The default value is 1000 each. -1 is unlimited but it could blow your memory.
• At PUB/SUB, PUB will drop messages silently when a connected sending pipe has more messages than HWM. Other available SUBs will can receive the messages.
• At PUSH/PULL, PUSH will block sending messages when there's no available PULL. Otherwise one of available PULL can receive the messages.
• If you're interested in LWM (Low Water Mark) also please refer compute_lwm at Pipe.java

JVM options

• -server -XX:+UseConcMarkSweepGC
• -XX:+TieredCompilation (if you're using the latest JVM)
• At java7, tiered compilation is now the default mode for the server VM
• -XX:+AggressiveOpts
• -XX:+UseCompressedOops might increase performance a little bit or not at 64bit OS
• enabled by default in Java SE 6u23 and later. In Java SE 7, use of compressed oops is the default for 64-bit JVM processes when -Xmx isn't specified and for values of -Xmx less than 32 gigabytes.
• -XX:+UseBiasedLocking might increase performance a little bit or not
• -XX:+UseNUMA could increase performance

Additional information

These slides may help if you want to contribute to the project. It visualizes the Internal Architecture of libzmq page.