Plug POST performance

Questions & Help Questions
4

Maybe I’m missing something, but the code in the repo seems to do more than that. If I simplify that top-level plug, to just return 204:

defmodule Icepick.PlugRouter do
  import Plug.Conn

  def init(options) do
    options
  end

  def call(conn, _opts) do
    conn
    |> send_resp(204, [])
  end

  def start_link() do
    {:ok, _} = Plug.Adapters.Cowboy.http(
      __MODULE__,
      [],
      [port: 8000])
  end
end

I get the following on my dev machine:

$ wrk -c 100 -d 60 -t 2 -s wrk.lua  http://localhost:8000/supply-partners/mopub
Running 1m test @ http://localhost:8000/supply-partners/mopub
  2 threads and 100 connections
  Thread Stats   Avg      Stdev     Max   +/- Stdev
    Latency    26.40ms   79.89ms 291.43ms   91.53%
    Req/Sec    22.38k     8.47k   46.78k    79.63%
  2510775 requests in 1.00m, 362.02MB read
Requests/sec:  41846.51

The latency here is still unusually large, but at least the throughput is way better (originally it was below 20k/sec).

Recently I demoed a simple Phoenix app which did some parameter decoding and json encoding (so a bit more work than this simple example), and I got a sub-micromillisecond 99th percentile latency with a wrk test (this same machine), so I’m pretty certain there’s room for improvements here.