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Till now we would keep a per-thread queue of pending incoming connections for which we would store: - the listener - the accepted FD - the source address - the source address' length And these elements were first used in session_accept_fd() running on the target thread to allocate a connection and duplicate them again. Doing this induces various problems. The first one is that session_accept_fd() may only run on file descriptors and cannot be reused for QUIC. The second issue is that it induces lots of memory copies and that the listerner queue thrashes a lot of cache, consuming 64 bytes per entry. This patch changes this by allocating the connection before queueing it, and by only placing the connection's pointer into the queue. Indeed, the first two calls used to initialize the connection already store all the information above, which can be retrieved from the connection pointer alone. So we just have to pop one pointer from the target thread, and pass it to session_accept_fd() which only needs the FD for the final settings. This starts to make the accept path a bit more transport-agnostic, and saves memory and CPU cycles at the same time (1% connection rate increase was noticed with 4 threads). Thanks to dividing the accept-queue entry size from 64 to 8 bytes, its size could be increased from 256 to 1024 connections while still dividing the overall size by two. No single queue full condition was met. One minor drawback is that connection may be allocated from one thread's pool to be used into another one. But this already happens a lot with connection reuse so there is really nothing new here.
The HAProxy documentation has been split into a number of different files for ease of use. 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)