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It is not rare to see configurations with a large number of "tcp-request content" or "http-request" rules for instance. A large number of rules combined with cpu-demanding actions (e.g.: actions that work on content) may create thread contention as all the rules from a given ruleset are evaluated under the same polling loop if the evaluation is not interrupted Thus, in this patch we add extra logic around "tcp-request content", "tcp-response content", "http-request" and "http-response" rulesets, so that when a certain number of rules are evaluated under the single polling loop, we force the evaluating function to yield. As such, the rule which was about to be evaluated is saved, and the function starts evaluating rules from the save pointer when it returns (in the next polling loop). We use task_wakeup(task, TASK_WOKEN_MSG) to explicitly wake the task so that no time is wasted and the processing is resumed ASAP. TASK_WOKEN_MSG is mandatory here because process_stream() expects TASK_WOKEN_MSG for explicit analyzers re-evaluation. rules_bcount stream's attribute was added to count how manu rules were evaluated since last interruption (yield). Also, SF_RULE_FYIELD flag was added to know that the s->current_rule was assigned due to forced yield and not regular yield. By default haproxy will enforce a yield every 50 rules, this behavior can be configured using the "tune.max-rules-at-once" global keyword. There is a limitation though: for now, if the ACT_OPT_FINAL flag is set on act_opts, we consider it is not safe to yield (as it is already the case for automatic yield). In this case instead of yielding an taking the risk of not being called back, we skip the yield and hope it will not create contention. This is something we should ideally try to improve in order to yield in all conditions.
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.