9fe72bba3c
For leastconn, servers used to just be stored in an ebtree. Each server would be one node. Change that so that nodes contain multiple mt_lists. Each list will contain servers that share the same key (typically meaning they have the same number of connections). Using mt_lists means that as long as tree elements already exist, moving a server from one tree element to another does no longer require the lbprm write lock. We use multiple mt_lists to reduce the contention when moving a server from one tree element to another. A list in the new element will be chosen randomly. We no longer remove a tree element as soon as they no longer contain any server. Instead, we keep a list of all elements, and when we need a new element, we look at that list only if it contains a number of elements already, otherwise we'll allocate a new one. Keeping nodes in the tree ensures that we very rarely have to take the lbrpm write lock (as it only happens when we're moving the server to a position for which no element is currently in the tree). The number of mt_lists used is defined as FWLC_NB_LISTS. The number of tree elements we want to keep is defined as FWLC_MIN_FREE_ENTRIES, both in defaults.h. The value used were picked afrer experimentation, and seems to be the best choice of performances vs memory usage. Doing that gives a good boost in performances when a lot of servers are used. With a configuration using 500 servers, before that patch, about 830000 requests per second could be processed, with that patch, about 1550000 requests per second are processed, on an 64-cores AMD, using 1200 concurrent connections.
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.