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by only storing a word in each thread context, we can keep the history of all taken/dropped locks by label. This is expected to be very cheap and to permit to store up to 8 consecutive lock operations in 64 bits. That should significantly help detect recursive locks as well as figure what thread was likely to hinder another one waiting for a lock. For now we only store the final state of the lock, we don't store the attempt to get it. It's just a matter of space since we already need 4 ops (rd,sk,wr,un) which take 2 bits, leaving max 64 labels. We're already around 45. We could also multiply by 5 and still keep 8 bits total per lock, that would limit us to 51 locks max. It seems that most of the time if we get a watchdog panic, anyway the victim thread will be perfectly located so that we don't need a specific value for this. Another benefit is that we perform a single memory write per lock.
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.