a9df6947b4
There's still a lot of contention when accessing the backend's
totpend and queueslength for every request in may_dequeue_tasks(),
even when queues are not used. This only happens because it's stored
in the same cache line as >beconn which is being written by other
threads:
0.01 | call sess_change_server
0.02 | mov 0x188(%r15),%esi ## s->queueslength
| if (may_dequeue_tasks(srv, s->be))
0.00 | mov 0xa8(%r12),%rax
0.00 | mov -0x50(%rbp),%r11d
0.00 | mov -0x60(%rbp),%r10
0.00 | test %esi,%esi
| jne 3349
0.01 | mov 0xa00(%rax),%ecx ## p->queueslength
8.26 | test %ecx,%ecx
4.08 | je 288d
This patch moves queueslength and totpend to their own cache line,
thus adding 64 bytes to the struct proxy, but gaining 3.6% of RPS
on a 64-core EPYC thanks to the elimination of this false sharing.
process_stream() goes down from 3.88% to 3.26% in perf top, with
the next top users being inc/dec (s->served) and be->beconn.
HAProxy
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:
- doc/intro.txt for a quick introduction on HAProxy
- doc/configuration.txt for the configuration's reference manual
- doc/lua.txt for the Lua's reference manual
- doc/SPOE.txt for how to use the SPOE engine
- doc/network-namespaces.txt for how to use network namespaces under Linux
- doc/management.txt for the management guide
- doc/regression-testing.txt for how to use the regression testing suite
- doc/peers.txt for the peers protocol reference
- doc/coding-style.txt for how to adopt HAProxy's coding style
- doc/internals for developer-specific documentation (not all up to date)
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.