HAProxy - Load balancer
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BUG/MINOR: mux-h2: send the preface along with the first request if needed
Tests involving 0-RTT and H2 on the backend show that 0-RTT is being
partially used but does not work. The analysis shows that only the
preface and settings are sent using early-data and the request is sent
separately. As explained in the previous patch, this is caused by the
fact that a wakeup of the iocb is needed just to send the preface, then
a new call to process_stream is needed to try sending again.

Here with this patch, we're making h2_snd_buf() able to send the preface
if it was not yet sent. Thanks to this, the preface, settings and first
request can now leave as a single TCP segment. In case of TLS with 0-RTT,
it now allows all the block to leave in early data.

Even in clear-text H2, we're now seeing a 15% lower context-switch count,
and the number of calls to process_stream() per connection dropped from 3
to 2. The connection rate increased by an extra 9.5%. Compared to without
the last 3 patches, this is a 22% reduction of context-switches, 33%
reduction of process_stream() calls, and 15.7% increase in connection
rate. And more importantly, 0-RTT now really works with H2 on the
backend, saving one full RTT on the first request.

This fix is only for a missed optimization and a non-functional 0-RTT
on the backend. It's worth backporting it, but it doesn't cause enough
harm to hurry a backport. Better wait for it to live a little bit in
3.3 (till at least a week or two after the final release) before
backporting it. It's not sure that it's worth going beyond 3.2 in any
case. It depends on the these two previous commits:

  MEDIUM: mux-h2: do not needlessly refrain from sending data early
  MINOR: mux-h2: extract the code to send preface+settings into its own function
2025-10-30 18:16:54 +01:00
.github CI: github: add USE_ECH=1 to haproxy for openssl-ech job 2025-10-30 10:38:38 +01:00
addons MINOR: applet: Add a flag to know an applet is using HTX buffers 2025-08-25 11:11:05 +02:00
admin ADMIN: reload: introduce -vv mode 2025-09-29 19:29:10 +02:00
dev DEV: patchbot: use git reset+checkout instead of pull 2025-10-08 04:38:35 +02:00
doc DOC: management: document ECH CLI commands 2025-10-30 11:59:39 +01:00
examples MINOR: mailers: warn if mailers are configured but not actually used 2025-06-27 16:41:18 +02:00
include MEDIUM: mux-h2: do not needlessly refrain from sending data early 2025-10-30 18:16:54 +01:00
reg-tests REGTEST: quic: add ssl_reuse.vtc new QUIC test 2025-10-30 08:33:54 +01:00
scripts CI: scripts: build curl with ECH support 2025-09-25 17:05:46 +02:00
src BUG/MINOR: mux-h2: send the preface along with the first request if needed 2025-10-30 18:16:54 +01:00
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 3.3-dev10 2025-10-18 11:24:05 +02:00
CONTRIBUTING CLEANUP: assorted typo fixes in the code and comments 2025-04-02 11:12:20 +02:00
INSTALL BUILD: makefile: bump the default minimum linux version to 4.17 2025-09-05 09:44:56 +02:00
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 MEDIUM: ssl/ech: config and load keys 2025-10-30 10:37:12 +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 3.3-dev10 2025-10-18 11:24:05 +02:00
VERSION [RELEASE] Released version 3.3-dev10 2025-10-18 11:24:05 +02:00

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.