4431e3bd26
perf top shows that sink_announce_dropped() consumes most of the CPU on a 128-thread x86 system. Digging further reveals that the atomic fetch_or() on the dropped field used to detect the presence of another thread is entirely responsible for this. Indeed, the compiler implements it using a CAS that loops without relaxing and makes all threads wait until they can synchronize on this one, only to discover later that another thread is there and they need to give up. Let's just replace this with a hand-crafted CAS loop that will detect *before* attempting the CAS if another thread is there. Doing so achieves the same goal without forcing threads to agree. With this simple change, the sustained request rate on h1 with all traces on bumped from 110k/s to 244k/s! This should be backported to stable releases where it's often needed to help debugging.
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.