wrk HTTP Benchmarking Tool

The output provides a summary of the benchmark results, including:

• Thread Stats: Average, standard deviation, and maximum values for Latency and Requests per second (Req/Sec).
• Summary Line: Total requests made, duration, and total data read.
• Requests/sec: The overall throughput of the benchmark.
• Transfer/sec: The overall data transfer rate.

Running 30s test @ http://127.0.0.1:8080/index.html
  12 threads and 400 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency   635.91us    0.89ms  12.92ms   93.69%
    Req/Sec    56.20k     8.07k   62.00k    86.54%
  22464657 requests in 30.00s, 17.76GB read
Requests/sec: 748868.53
Transfer/sec:    606.33MB

To achieve maximum load and accurate results, consider the following:

System Configuration

• Ephemeral Ports: Ensure the machine running wrk has a sufficient number of ephemeral ports available.
• Socket Recycling: Ensure closed sockets are recycled quickly by the OS.
• Server Backlog: To handle the initial connection burst, the server's listen(2) backlog should be greater than the number of concurrent connections being tested.

Scripting Performance

• Low Impact: Using a LuaJIT script to only change the HTTP method, path, headers, or body has negligible performance impact.
• High Impact: Per-request actions, specifically building a new HTTP request from scratch or using the response() function, will reduce the total amount of load wrk can generate.

To perform a standard HTTP benchmark, provide the target URL and use flags to specify the number of threads, connections, and duration.

Example: Running a benchmark for 30 seconds using 12 threads and 400 concurrent connections.

wrk -t12 -c400 -d30s http://127.0.0.1:8080/index.html

Use the following flags to configure your benchmark execution:

• -c, --connections: Total number of HTTP connections to keep open. Each thread handles N = connections/threads connections.
• -d, --duration: Duration of the test (e.g., 2s, 2m, 2h).
• -t, --threads: Total number of threads to use.
• -s, --script: Path to a LuaJIT script for custom request generation or response processing.
• -H, --header: HTTP header to add to the request (e.g., "User-Agent: wrk").
• --latency: Print detailed latency statistics in the output.
• --timeout: Record a timeout if a response is not received within the specified amount of time.