‘read-line’ benchmark

[Ludovic Courtès]

Hello!

I pushed a micro-benchmark, which I used to compare the new
implementation of ‘read-line’ (commit
e578faea202a4e6eeb32e81e489b59119a2e02a0) to the previous one (before
a2c36371ce3de246bdb892afd50915ecf450df47):

  * before:

   ("ports.bm: rdelim: read-line" 1000 user 5.2)

  * after:

   ("ports.bm: rdelim: read-line" 1000 user 3.72)

A 30% improvement, yay!  (Indeed, we had reports of unexpected web
server speedups on IRC today.  ;-))

Thanks,
Ludo’.