From 7078fb1f3a11b1af3170e47cbc250387b3eb6ee5 Mon Sep 17 00:00:00 2001 From: Amaury Denoyelle Date: Tue, 22 Nov 2022 11:26:16 +0100 Subject: [PATCH] DOC: quic: add note on performance issue with listener contention Complete quic4/quic6 bind lines by a note on performance issues due to receiver socket contention. Suggest to use sharding to improve the situation. This should be backported up to 2.6. --- doc/configuration.txt | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/doc/configuration.txt b/doc/configuration.txt index c3d4ea5cc..d0ce0ab52 100644 --- a/doc/configuration.txt +++ b/doc/configuration.txt @@ -4563,9 +4563,15 @@ bind / [, ...] [param*] to receive a FD over the unix socket and uses it as if it was the FD of an accept(). Should be used carefully. - 'quic4@' -> address is resolved as IPv4 and protocol UDP - is used. + is used. Note that QUIC connections attached to a + listener will be multiplexed over the listener socket. + With a large traffic this has a noticeable impact on + performance and CPU consumption. To improve this, you + should duplicate QUIC listener instances over several + threads, for example using "shards" keyword. - 'quic6@' -> address is resolved as IPv6 and protocol UDP - is used. + is used. The performance note for QUIC over IPv4 applies + as well. You may want to reference some environment variables in the address parameter, see section 2.3 about environment