[nigrosimone]

A {n} in the path becomes a number that changes on every request, so a server cannot answer from the bytes of the request before. The varied URLs case from uNetworking/uWebSockets.js#1352:

http_load_test 50 localhost 3000 /user/{n} 4

The number has a fixed width (8 digits) and is written in place before each send, so the request keeps its size. Without {n} nothing changes.

Checked against a uWS.js app counting urls: 696108 requests, 696108 distinct urls, and /user/0 gives one. Same req/s with and without {n} (the server on one core is the limit).

[uNetworkingAB]

Waaaait. It shouldn't be pipelined. I never benchmark pipelined. It just a variation for keep-alive.

[nigrosimone]

It is not pipelined: pipeline is still 1 unless you pass the pipeline factor (the 5th argument, from 9e1ccc7). With 1 the loop in vary_request runs once, so one request with a new number per write, sent after the previous response. The loop is only there so a pipelined batch gets different numbers too.