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.

Comparisons of Aeron with other algorithms for RTT IPC latency can be found here.

Throughput Testing

System Preparation

Adjust socket limits:

Linux

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

FreeBSD / Darwin

$ sysctl -w kern.ipc.maxsockbuf=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.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.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=32 \
    -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=32 \
    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=32 \
    -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)