tcpulse is a high-performance TCP and UDP load generator designed with fine-grained, flow-level control in Go. This tool facilitates effective measurement and analysis of network connection performance. Users can operate tcpulse in two distinct modes:

• Server Mode (-s/--server): Functions as an echo server, accepting TCP/UDP connections and sending back received data.
• Client Mode (-c/--client): Generates configurable load on target servers while measuring performance metrics.

Key Benefits of Using tcpulse

tcpulse is essential for various network performance testing scenarios including:

• Load Testing: Determine server capacity and identify potential bottlenecks prior to production deployment.
• Connection Performance Measurement: Assess the speed of new connection establishment and sustained connection performance metrics such as throughput and latency.
• Protocol Comparison: Evaluate and compare the performance characteristics of TCP versus UDP.
• Infrastructure Validation: Ensure that network infrastructure can handle anticipated traffic patterns.
• Performance Regression Testing: Detect any performance degradations in network services over time.

Operational Modes

tcpulse supports two connection patterns to mimic real-world usage:

1. Persistent Connections: Maintains long-lived connections, sending multiple requests per connection, simulating connection pooling applications such as web services and databases.
2. Ephemeral Connections: Establishes new connections for each request, closing them immediately, thereby simulating scenarios typical in HTTP/1.0 or assessing connection establishment overhead.

Features

• Real-time Metrics: Provides latency percentiles (90th, 95th, 99th), throughput, and connection summaries.
• Rate Limiting: Control connection establishment rates to emulate realistic load patterns.
• Multi-target Support: Test multiple endpoints concurrently and aggregate results for comprehensive analysis.
• Protocol Support: Offers optimized implementations for both TCP and UDP.
• Platform Optimizations: Enhances performance by leveraging Linux-specific optimizations like TCP_FASTOPEN and SO_REUSEPORT.
• JSON Lines Output: Outputs results in a machine-readable format compatible with monitoring and analysis tools.

Usage Examples

To run tcpulse as a server:

$ tcpulse -s 127.0.0.1:9100

To generate load as a client:

$ tcpulse -c --flavor ephemeral --rate 1000 --duration 15s 127.0.0.1:9100

To test sustained connections:

$ tcpulse -c --flavor persistent --connections 1000 --duration 15s 127.0.0.1:9100

To conduct UDP load testing:

$ tcpulse -c --proto udp --rate 1000 --duration 15s 127.0.0.1:9100

The results can be output in JSON Lines format for further integration with monitoring tools:

$ tcpulse -c --jsonlines --rate 1000 --duration 10s 127.0.0.1:9100
{
  "peer":"127.0.0.1:9100",
  "count":9998,
  "latency_max_us":2156,
  "latency_min_us":145,
  "latency_mean_us":234,
  "latency_90p_us":289,
  "latency_95p_us":321,
  "latency_99p_us":456,
  "rate_per_sec":999.8,
  "timestamp":"2025-01-07T10:30:00Z"
}

tcpulse is a valuable tool for engineers and developers focused on enhancing network performance and reliability.