Since the introduction of speculative I/O, it was not always possible
to correctly detect a connection establishment. Particularly, in TCP
mode, there is no data to send and getsockopt() returns no error. The
solution consists in trying a connect() again to get its diagnostic.
tv_cmp2_ms handles multiple combinations of tv1 and tv2, but only
one form is used: (tv1 <= tv2). So it is overkill to use it everywhere.
A new function designed to do exactly this has been written for that
purpose: tv_cmp2_le. Also, removed old unused tv_* functions.
The fact that TV_ETERNITY was 0 was very awkward because it
required that comparison functions handled the special case.
Now it is ~0 and all comparisons are performed on unsigned
values, so that it is naturally greater than any other value.
A performance gain of about 2-5% has been noticed.
The rbtree-based wait queue consumes a lot of CPU. Use the ul2tree
instead. Lots of cleanups and code reorganizations made it possible
to reduce the task struct and simplify the code a bit.
- modularized the polling mechanisms and use function pointers instead
of macros at many places
- implemented support for FreeBSD's kqueue() polling mechanism
- fixed a warning on OpenBSD : MIN/MAX redefined
- change socket registration order at startup to accomodate kqueue.
- several makefile cleanups to support old shells
- fix build with limits.h once for all
- ev_epoll: do not rely on fd_sets anymore, use changes stacks instead.
- fdtab now holds the results of polling
- implemented support for speculative I/O processing with epoll()
- remove useless calls to shutdown(SHUT_RD), resulting in small speed boost
- auto-registering of pollers at load time
The principle behind speculative I/O is to speculatively try to
perform I/O before registering the events in the system. This
considerably reduces the number of calls to epoll_ctl() and
sometimes even epoll_wait(), and manages to increase overall
performance by about 10%.
The new poller has been called "sepoll". It is used by default
on Linux when it works. A corresponding option "nosepoll" and
the command line argument "-ds" allow to disable it.
Gcc provides __attribute__((constructor)) which is very convenient
to execute functions at startup right before main(). All the pollers
have been converted to have their register() function declared like
this, so that it is not necessary anymore to call them from a centralized
file.
The pollers will now be able to speculatively call the I/O
processing functions and decide whether or not they want to
poll on those FDs. The changes primarily consist in teaching
those functions how to pass the info they got an EAGAIN.
Now fdtab can contain the FD_POLL_* events so that the pollers
which can fill them can give userful information to readers and
writers about the precise condition of wakeup.
It may be dangerous to play with fdtab before doing fd_insert()
because this last one is responsible for growing maxfd as needed.
Call fd_insert() before instead.
Patch #cf83df3d162687d9c74783357421bd89f596eaac was stupid. Including
limits.h is portable and easier. At least it now builds on Solaris,
FreeBSD, Linux and OpenBSD.
Some pollers such as kqueue lose their FD across fork(), meaning that
the registered file descriptors are lost too. Now when the proxies are
started by start_proxies(), the file descriptors are not registered yet,
leaving enough time for the fork() to take place and to get a new pollfd.
It will be the first call to maintain_proxies that will register them.
FreeBSD stores INT_MIN and INT_MAX in sys/limits.h only. Other systems
(Solaris) have it in sys/types.h and do not have sys/limits.h. Let's
include sys/limits.h only if INT_MAX is not defined.
select, poll and epoll now have their dedicated functions and have
been split into distinct files. Several FD manipulation primitives
have been provided with each poller.
The rest of the code needs to be cleaned to remove traces of
StaticReadEvent/StaticWriteEvent. A trick involving a macro has
temporarily been used right now. Some work needs to be done to
factorize tests and sets everywhere.
- rewriting either the status line or request line could crash the
process due to a pointer which ought to be reset before parsing.
- rewriting the status line in the response did not work, it caused
a 502 Bad Gateway due to an erroneous state during parsing
