HAProxy - Load balancer
Find a file
Willy Tarreau a79a67b52f OPTIM: server: get rid of the last use of _ha_barrier_full()
The code in srv_add_to_idle_list() has its roots in 2.0 with commit
9ea5d361ae ("MEDIUM: servers: Reorganize the way idle connections are
cleaned."). At this era we didn't yet have the current set of atomic
load/store operations and we used to perform loads using volatile casts
after a barrier. It turns out that this function has kept this schema
over the years, resulting in a big mfence stalling all the pipeline
in the function:

       |     static __inline void
       |     __ha_barrier_full(void)
       |     {
       |     __asm __volatile("mfence" ::: "memory");
 27.08 |       mfence
       |     if ((volatile void *)srv->idle_node.node.leaf_p == NULL) {
  0.84 |       cmpq    $0x0,0x158(%r15)
  0.74 |       je      35f
       |     return 1;

Switching these for a pair of atomic loads got rid of this and brought
0.5 to 3% extra performance depending on the tests due to variations
elsewhere, but it has never been below 0.5%. Note that the second load
doesn't need to be atomic since it's protected by the lock, but it's
cleaner from an API and code review perspective. That's also why it's
relaxed.

This was the last user of _ha_barrier_full(), let's try not to
reintroduce it now!
2026-01-28 16:07:27 +00:00
.github CI: github: fix vtest.yml with "not quictls" 2026-01-19 13:22:10 +01:00
addons BUG/MINOR: promex: Detach promex from the server on error dump its metrics dump 2026-01-23 11:40:54 +01:00
admin MEDIUM: systemd: implement directory loading 2026-01-16 09:55:33 +01:00
dev CLEANUP: use the automatic alignment feature 2025-12-09 17:14:58 +01:00
doc DOC: config: mention some possible TLS versions restrictions for kTLS 2026-01-28 10:45:21 +01:00
examples MINOR: mailers: warn if mailers are configured but not actually used 2025-06-27 16:41:18 +02:00
include OPTIM: proxy: separate queues fields from served 2026-01-28 16:07:27 +00:00
reg-tests REGTESTS: ssl: fix generate-certificates w/ LibreSSL 2026-01-21 16:50:16 +01:00
scripts SCRIPTS: build: enable symbols in AWS-LC builds 2026-01-22 15:25:24 +01:00
src OPTIM: server: get rid of the last use of _ha_barrier_full() 2026-01-28 16:07:27 +00:00
tests TESTS: quic: add unit-tests for QUIC TX part 2025-09-08 14:49:03 +02:00
.cirrus.yml CI: cirrus-ci: bump FreeBSD image to 14-3 2025-10-09 14:06:48 +02:00
.gitattributes MINOR: Configure the cpp userdiff driver for *.[ch] in .gitattributes 2021-02-22 18:17:57 +01:00
.gitignore MINOR: tevt/dev: Add term_events tool 2025-01-31 10:41:50 +01:00
.mailmap DOC: update Tim's address in .mailmap 2021-09-16 09:14:14 +02:00
.travis.yml MEDIUM: mworker: remove USE_SYSTEMD requirement for -Ws 2024-11-20 12:07:38 +01:00
BRANCHES DOC: clarify the experimental status for certain features 2025-10-17 18:41:13 +02:00
BSDmakefile BUILD: makefile: commit the tiny FreeBSD makefile stub 2023-05-24 17:17:36 +02:00
CHANGELOG [RELEASE] Released version 3.4-dev3 2026-01-22 19:02:54 +01:00
CONTRIBUTING CLEANUP: assorted typo fixes in the code and comments 2025-04-02 11:12:20 +02:00
INSTALL MINOR: version: mention that it's development again 2025-11-26 16:11:47 +01:00
LICENSE LICENSE: add licence exception for OpenSSL 2012-09-07 13:52:26 +02:00
MAINTAINERS MAJOR: spoe: Let the SPOE back into the game 2024-05-22 09:04:38 +02:00
Makefile REORG: cfgparse: move peers parsing to cfgparse-peers.c 2026-01-20 17:17:37 +01:00
README.md DOC: change the link to the FreeBSD CI in README.md 2024-06-03 15:21:29 +02:00
SUBVERS BUILD: use format tags in VERDATE and SUBVERS files 2013-12-10 11:22:49 +01:00
VERDATE [RELEASE] Released version 3.4-dev3 2026-01-22 19:02:54 +01:00
VERSION [RELEASE] Released version 3.4-dev3 2026-01-22 19:02:54 +01:00

HAProxy

alpine/musl AWS-LC openssl no-deprecated Illumos NetBSD FreeBSD VTest

HAProxy logo

HAProxy is a free, very fast and reliable reverse-proxy offering high availability, load balancing, and proxying for TCP and HTTP-based applications.

Installation

The INSTALL file describes how to build HAProxy. A list of packages is also available on the wiki.

Getting help

The discourse and the mailing-list are available for questions or configuration assistance. You can also use the slack or IRC channel. Please don't use the issue tracker for these.

The issue tracker is only for bug reports or feature requests.

Documentation

The HAProxy documentation has been split into a number of different files for ease of use. It is available in text format as well as HTML. The wiki is also meant to replace the old architecture guide.

Please refer to the following files depending on what you're looking for:

  • INSTALL for instructions on how to build and install HAProxy
  • BRANCHES to understand the project's life cycle and what version to use
  • LICENSE for the project's license
  • CONTRIBUTING for the process to follow to submit contributions

The more detailed documentation is located into the doc/ directory:

License

HAProxy is licensed under GPL 2 or any later version, the headers under LGPL 2.1. See the LICENSE file for a more detailed explanation.