I'm not what is going on, but you could try eliminating a few things. 1) Is it a TCP protocol behaviour (e.g. slow start)? Test this by implementing the same thing using UDP. 2) Are your CPUs going to sleep? Test by locking the CPU frequency scaling and/or setting the power management for the CPU to performance mode.
Mike. On 13 April 2017 at 07:56, J Crawford <[email protected]> wrote: > The SO question has the source codes of a simple server and client that > demonstrate and isolate the problem. Basically I'm timing the latency of a > ping-pong (client-server-client) message. I start by sending one message > every 1 millisecond. I wait for 200k messages to be sent so that the > HotSpot has a chance to optimize the code. Then I change my pause time from > 1 millisecond to 30 seconds. For my surprise my write and read operation > become considerably slower. > > I don't think it is a JIT/HotSpot problem. I was able to pinpoint the > slower method to the native JNI calls to write (write0) and read. Even if I > change the pause from 1 millisecond to 1 second, problem persists. > > I was able to observe that on MacOS and Linux. > > Does anyone here have a clue of what can be happening? > > Note that I'm disabling Nagle's Algorithm with setTcpNoDelay(true). > > SO question with code and output: http://stackoverflow. > com/questions/43377600/socketchannel-why-if-i-write- > msgs-quickly-the-latency-of-each-message-is-low-b > > Thanks! > > -JC > > -- > You received this message because you are subscribed to the Google Groups > "mechanical-sympathy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "mechanical-sympathy" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
