mirror of
https://git.haproxy.org/git/haproxy.git/
synced 2025-09-21 05:41:26 +02:00
ccf3f6d1d6
In order to address the absurd polling sequence described in issue #253, let's make sure we disable receiving on a connection until it's established. Previously with bottom-top I/Os, we were almost certain that a connection was ready when the first I/O was confirmed. Now we can enter various functions, including process_stream(), which will attempt to read something, will fail, and will then subscribe. But we don't want them to try to receive if we know the connection didn't complete. The first prerequisite for this is to mark the connection as not ready for receiving until it's validated. But we don't want to mark it as not ready for sending because we know that attempting I/Os later is extremely likely to work without polling. Once the connection is confirmed we re-enable recv readiness. In order for this event to be taken into account, the call to tcp_connect_probe() was moved earlier, between the attempt to send() and the attempt to recv(). This way if tcp_connect_probe() enables reading, we have a chance to immediately fall back to this and read the possibly pending data. Now the trace looks like the following. It's far from being perfect but we've already saved one recvfrom() and one epollctl(): epoll_wait(3, [], 200, 0) = 0 socket(AF_INET, SOCK_STREAM, IPPROTO_TCP) = 7 fcntl(7, F_SETFL, O_RDONLY|O_NONBLOCK) = 0 setsockopt(7, SOL_TCP, TCP_NODELAY, [1], 4) = 0 connect(7, {sa_family=AF_INET, sin_port=htons(8000), sin_addr=inet_addr("127.0.0.1")}, 16) = -1 EINPROGRESS (Operation now in progress) epoll_ctl(3, EPOLL_CTL_ADD, 7, {EPOLLIN|EPOLLOUT|EPOLLRDHUP, {u32=7, u64=7}}) = 0 epoll_wait(3, [{EPOLLOUT, {u32=7, u64=7}}], 200, 1000) = 1 connect(7, {sa_family=AF_INET, sin_port=htons(8000), sin_addr=inet_addr("127.0.0.1")}, 16) = 0 getsockopt(7, SOL_SOCKET, SO_ERROR, [0], [4]) = 0 sendto(7, "OPTIONS / HTTP/1.0\r\n\r\n", 22, MSG_DONTWAIT|MSG_NOSIGNAL, NULL, 0) = 22 epoll_ctl(3, EPOLL_CTL_MOD, 7, {EPOLLIN|EPOLLRDHUP, {u32=7, u64=7}}) = 0 epoll_wait(3, [{EPOLLIN|EPOLLRDHUP, {u32=7, u64=7}}], 200, 1000) = 1 getsockopt(7, SOL_SOCKET, SO_ERROR, [0], [4]) = 0 getsockopt(7, SOL_SOCKET, SO_ERROR, [0], [4]) = 0 recvfrom(7, "HTTP/1.0 200\r\nContent-length: 0\r\nX-req: size=22, time=0 ms\r\nX-rsp: id=dummy, code=200, cache=1, size=0, time=0 ms (0 real)\r\n\r\n", 16384, 0, NULL, NULL) = 126 close(7) = 0
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)