Performance Testing

Aeron is designed to provide high-throughput and low-latency message transport from publishers to subscribers.

A number of tests are provided in the samples module to test both latency and throughput.

Throughput Testing

System Preparation

Adjust Linux socket limits:

$ sudo sysctl net.core.rmem_max=2097152
$ sudo sysctl net.core.wmem_max=2097152

Explanation of configuration options:

• -XX:BiasedLockingStartupDelay=0: The driver has no contended locks so can benefit from avoiding the CAS operations to take a lock.
• -Daeron.mtu.length=16384: Increase the size of the maximum transmission unit to reduce system calls in a throughput scenario.
• -Daeron.rcv.buffer.length=16384: Increase the size of the Aeron receive buffer to accommodate the MTU.
• -Daeron.socket.so_sndbuf=2097152: Increase the size of OS socket send buffer (SO_SNDBUF) to account for Bandwidth Delay Product (BDP) on a high bandwidth network.
• -Daeron.socket.so_rcvbuf=2097152: Increase the size of OS socket receive buffer (SO_RCVBUF) to account for Bandwidth Delay Product (BDP) on a high bandwidth network.
• -Daeron.rcv.initial.window.length=2097152: Set the initial window for flow control to account for BDP.
• -Dagrona.disable.bounds.checks=true: Disable bound checking to reduce instruction path on private secure networks.
• -XX:+UnlockDiagnosticVMOptions -XX:GuaranteedSafepointInterval=300000: To reduce the frequency of the JVM bringing all threads to a safepoint.

Execution

Run the media driver:

$ java -cp aeron-samples/build/libs/samples.jar \
    -XX:BiasedLockingStartupDelay=0 \
    -Daeron.mtu.length=16384 \
    -Daeron.rcv.buffer.length=16384 \
    -Daeron.socket.so_sndbuf=2097152 \
    -Daeron.socket.so_rcvbuf=2097152 \
    -Daeron.rcv.initial.window.length=2097152 \
    -Dagrona.disable.bounds.checks=true \
    io.aeron.samples.LowLatencyMediaDriver

Run the Subscriber:

$ java -cp aeron-samples/build/libs/samples.jar \
    -Dagrona.disable.bounds.checks=true \
    -Daeron.sample.frameCountLimit=256 \
    io.aeron.samples.RateSubscriber

Run the Publisher:

$ java -cp aeron-samples/build/libs/samples.jar \
    -Daeron.sample.messageLength=40 \
    -Daeron.sample.messages=500000000 \
    -Dagrona.disable.bounds.checks=true \
    io.aeron.samples.StreamingPublisher

IPC throughput via Shared Memory that bypasses the network:

$ java -cp aeron-samples/build/libs/samples.jar \
    -Dagrona.disable.bounds.checks=true \
    -Daeron.sample.messageLength=40 \
    io.aeron.samples.EmbeddedIpcThroughput

Latency Testing

System Preparation

Currently no specific changes required.

Execution

Run the media driver:

$ java -cp aeron-samples/build/libs/samples.jar \
    -XX:+UnlockDiagnosticVMOptions \
    -XX:GuaranteedSafepointInterval=300000 \
    -XX:BiasedLockingStartupDelay=0 \
    -Dagrona.disable.bounds.checks=true \
    io.aeron.samples.LowLatencyMediaDriver

Run the Subscriber:

$ java -cp aeron-samples/build/libs/samples.jar \
    -XX:+UnlockDiagnosticVMOptions \
    -XX:GuaranteedSafepointInterval=300000 \
    -Dagrona.disable.bounds.checks=true \
    io.aeron.samples.Pong

Run the Publisher:

$ java -cp aeron-samples/build/libs/samples.jar \
    -XX:+UnlockDiagnosticVMOptions \
    -XX:GuaranteedSafepointInterval=300000 \
    -Daeron.sample.messages=100000 \
    -Daeron.sample.messageLength=40 \
    -Dagrona.disable.bounds.checks=true \
    io.aeron.samples.Ping

Profiling

• Java Flight Recorder: -XX:+UnlockCommercialFeatures -XX:+FlightRecorder -XX:+UnlockDiagnosticVMOptions -XX:+DebugNonSafepoints
• Get the hotspot compiler log: -XX:+UnlockDiagnosticVMOptions -XX:+TraceClassLoading -XX:+LogCompilation -XX:+PrintAssembly (see also http://mechanical-sympathy.blogspot.co.uk/2013/06/printing-generated-assembly-code-from.html)