Hi David, Thank you for the advice. I didn't think the tcpNoDelay would have an effect since I was looking at relatively large messages :) Simply changing the connection URL solved the immediate problem, send latency dropped right down into the microseconds as expected. So far I haven't had to make the suggested changes to the broker.
Ben davidmc wrote: > > Hi there bwatrous, > > Your average sent time for the problematic RUN 1 (40ms) indicates that > your problem is most probably caused by the bad Nagle's algorithm / > Delayed ACK timeout interaction. This timeout is 40ms in Linux and 200ms > in Windows / other systems. > > In short, the solution is to enable TCP_NODELAY flag on all your sockets. > -This is possible in the ActiveMQ CPP client since version 2.0.1. You > should append tcpNoDelay=true to the connection URL. > -On the broker's side, you should enable the TCP_NODELAY flag in the > broker's sockets. For this, following the documentation, you should append > 'wireFormat.tcpNoDelayEnabled=true' to your connector's URI. > In fact, this doesn't work and it is silently ignored. I discovered that > 'socket.tcpNoDelay=true' works if you append it to an ActiveMQ Java > CLIENT's connection URI; but it still doesn't work for a BROKER's > connector URI. > So, the only solution is to go to the broker's source code > (org.apache.activemq.transport.tcp.TcpTransport.initialiseSocket method) > and add the following line of Java code: > ---> sock.setTcpNoDelay(true); <--- > at the end of the method, so that all broker's sockets are created with > TCP_NODELAY=true by default. > > The parsing of options in a broker's activemq.xml connector URI is broken > right now, and it sadly doesn't seem to be a priority that this is fixed > for next releases. > So, I wonder how many folks encounter this '40 ms' problem, and when they > finally guess that the solution is the TCP_NODELAY flag (not so easy), > they try it and think it was not the right solution because > 'wireFormat.tcpNoDelayEnabled=true' or 'tcpNoDelay=true' or > 'socket.tcpNoDelay=true' get all silently ignored (no error message, but > no effect on the sockets). Probably lots of frustration and lost hours... > :( > > Related messages and JIRA's: > https://issues.apache.org/activemq/browse/AMQ-1156 > https://issues.apache.org/activemq/browse/AMQ-1137 > http://issues.apache.org/activemq/browse/AMQ-1233 > http://www.nabble.com/AMQCPP-Openwire-much-slower-than-Stomp--tf3599986s2354.html#a10055544 > -- View this message in context: http://www.nabble.com/CPP-client%3A-high-latency-for-large-messages-tf3995387s2354.html#a11361530 Sent from the ActiveMQ - User mailing list archive at Nabble.com.
