Link Module

The Link module benchmarks cluster replication link latency, measuring the performance of the low-level transport used for replicating state between cluster members.

Overview

The Link layer provides the foundation for cluster replication in X Platform, offering:

• Direct point-to-point communication between cluster members

• Minimal overhead transport for state replication

• Support for various network protocols (TCP, UDP, InfiniBand, etc.)

This benchmark measures the raw performance capabilities of the replication link layer.

Test Programs

StreamingSender / StreamingReceiver

Measures unidirectional throughput:

Sender Class: com.neeve.perf.link.StreamingSender Receiver Class: com.neeve.perf.link.StreamingReceiver

The sender continuously sends messages to the receiver as fast as possible, measuring maximum sustained throughput.

PingPongSender / PingPongReceiver

Measures round-trip latency:

Sender Class: com.neeve.perf.link.PingPongSender Receiver Class: com.neeve.perf.link.PingPongReceiver

The sender sends a message and waits for a response from the receiver, measuring round-trip time.

Use Cases

Streaming Test

Purpose: Measure maximum throughput Setup: Two machines connected via high-speed network Use Case: Validate network configuration and capacity

Ping-Pong Test

Purpose: Measure minimum latency Setup: Two machines connected via low-latency network Use Case: Validate network tuning and baseline latency

Running Benchmarks

Streaming Throughput Test

On Receiver Machine:

$JAVA_HOME/bin/java -cp "libs/*" com.neeve.perf.link.StreamingReceiver \
  --bind 0.0.0.0:5000

On Sender Machine:

$JAVA_HOME/bin/java -cp "libs/*" com.neeve.perf.link.StreamingSender \
  --target receiver.example.com:5000 \
  --count 10000000 \
  --messageSize 256

Ping-Pong Latency Test

On Receiver Machine:

$JAVA_HOME/bin/java -cp "libs/*" com.neeve.perf.link.PingPongReceiver \
  --bind 0.0.0.0:5000

On Sender Machine:

$JAVA_HOME/bin/java -cp "libs/*" com.neeve.perf.link.PingPongSender \
  --target receiver.example.com:5000 \
  --count 100000 \
  --messageSize 256

Interpreting Results

Throughput Results

Messages sent: 10000000
Duration: 45.2 seconds
Throughput: 221,238 messages/second
Bandwidth: 452 Mbps

Latency Results

Round-trip latency statistics:
  50th percentile: 42.5 µs
  99th percentile: 58.3 µs
  99.9th percentile: 82.1 µs

Network Configurations

TCP over 10GbE

Typical Results:

• Throughput: 1-2M messages/second

• Latency: 15-25µs round-trip

TCP over InfiniBand

Typical Results:

• Throughput: 2-4M messages/second

• Latency: 8-15µs round-trip

RDMA over InfiniBand

Typical Results:

• Throughput: 5-10M messages/second

• Latency: 2-5µs round-trip

Comparison with Higher Layers

Link layer provides the foundation for cluster replication:

• Link Layer: ~10µs (raw replication transport)

• Messaging Layer: ~15µs (adds SMA abstractions)

• AEP Engine: ~27µs (adds transactions, persistence, full clustering with consensus)

Next Steps

• Review Messaging Module for SMA layer benchmarks

• Review AEP Module for end-to-end benchmarks

• Return to Modules Overview for other modules