wrk

wrk is a multi-threaded HTTP benchmarking tool used for the static file serving test profile.

Why wrk for static files?

The static file test serves 20 files with response sizes ranging from 3 KB to 67 KB (brotli-compressed). At these sizes, gcannon’s io_uring provided buffer ring path introduces per-completion overhead that limits throughput to ~14 GB/s on loopback. wrk’s simpler epoll + read() approach achieves ~19 GB/s on the same workload, ensuring the load generator is never the bottleneck.

For small-response tests (baseline, JSON, pipelined), gcannon’s io_uring batched submission is faster than wrk. The tools complement each other.

Lua rotation script

wrk uses a Lua script (requests/static-rotate.lua) to cycle through all 20 static file paths. Each request includes Accept-Encoding: br;q=1, gzip;q=0.8 to test compressed file serving.

request = function()
  counter = counter + 1
  local path = paths[((counter - 1) % 20) + 1]
  return wrk.format("GET", path, {["Accept-Encoding"] = ae_header})
end

Parameters