tree 42e19696377419a5c2c19bfd0e42e008251b86e8
parent 06e69b556ce5839f74d82698350301d50e3b46ca
author Ubuntu <ubuntu@ip-172-31-37-79.us-east-2.compute.internal> 1614585474 +0000
committer Willy Tarreau <w@1wt.eu> 1614929408 +0100
encoding latin1

OPTIM: lb-random: use a cheaper PRNG to pick a server

The PRNG used by the "random" LB algorithm was the central one which tries
hard to produce "correct" (i.e. hardly predictable) values suitable for use
in UUIDs or cookies. It's much too expensive for pure load balancing where
a cheaper thread-local PRNG is sufficient, and the current PRNG is part of
the hot places when running with many threads.

Let's switch to the stastistical PRNG instead, it's thread-local, very
fast, and with a period of (2^32)-1 which is more than enough to decide
on a server.