5d0f5f8168
This introduces 3 new settings: tune.h2.be.max-frames-at-once and tune.h2.fe.max-frames-at-once, which limit the number of frames that will be processed at once for backend and frontend side respectively, and tune.h2.fe.max-rst-at-once which limits the number of RST_STREAM frames processed at once on the frontend. We can now yield when reading too many frames at once, which allows to limit the latency caused by processing too many frames in large buffers. However if we stop due to the RST budget being depleted, it's most likely the sign of a protocol abuse, so we make the tasklet go to BULK since the goal is to punish it. By limiting the number of RST per loop to 1, the SSL response time drops from 95ms to 1.6ms during an H2 RST flood attack, and the maximum SSL connection rate drops from 35.5k to 28.0k instead of 11.8k. A moderate SSL load that shows 1ms response time and 23kcps increases to 2ms with 15kcps versus 95ms and 800cps before. The average loop time goes down from 270-280us to 160us, while still doubling the attack absorption rate with the same CPU capacity. This patch may usefully be backported to 3.3 and 3.2. Note that to be effective, this relies on the following patches: MEDIUM: sched: do not run a same task multiple times in series MINOR: sched: do not requeue a tasklet into the current queue MINOR: sched: do not punish self-waking tasklets anymore MEDIUM: sched: do not punish self-waking tasklets if TASK_WOKEN_ANY MEDIUM: sched: change scheduler budgets to lower TL_BULK |
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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.