X-Git-Url: https://git.llucax.com/software/libev.git/blobdiff_plain/cc75a05531d9d05ac14fdaec7960b1c970c87bbb..a04347e5cbe92a5f99231dcdb3d7d0f474bad401:/README diff --git a/README b/README index 4e8ec2d..ee8f492 100644 --- a/README +++ b/README @@ -1,9 +1,92 @@ -libev is modelled after libevent (http://monkey.org/~provos/libevent/), but aims -to be faster and more correct, and also more featureful. Examples: - -- multiple watchers can wait for the same event without deregistering others. -- fork() is supported and can be handled. -- timers are handled as a priority queue (faster) -- watchers use less memory (faster) -- less calls to epoll_ctl (faster) +Homepage: http://software.schmorp.de/pkg/libev +E-Mail: libev@schmorp.de + +libev is a high-performance event loop/event model with lots of features. + +It is modelled (very losely) after libevent +(http://monkey.org/~provos/libevent/) and the Event perl module, but aims +to be faster and more correct, and also more featureful. + +DIFFERENCES AND COMPARISON TO LIBEVENT: + +(comparisons relative to libevent-1.3e and libev-0.00, see also the benchmark +at http://libev.schmorp.de/bench.html). + +- multiple watchers can wait for the same event without deregistering others, + both for file descriptors as well as signals. + (registering two read events on fd 10 and unregistering one will not + break the other). + +- fork() is supported and can be handled + (there is no way to recover from a fork when libevent is active). + +- timers are handled as a priority queue (important operations are O(1)) + (libevent uses a much less efficient but more complex red-black tree). + +- supports absolute (wallclock-based) timers in addition to relative ones, + i.e. can schedule timers to occur after n seconds, or at a specific time. + +- timers can be repeating (both absolute and relative ones). + +- detects time jumps and adjusts timers + (works for both forward and backward time jumps and also for absolute timers). + +- race-free signal processing + (libevent may delay processing signals till after the next event). + +- less calls to epoll_ctl + (stopping and starting an io watcher between two loop iterations will now + result in spuriois epoll_ctl calls). + +- usually less calls to gettimeofday and clock_gettime + (libevent calls it on every timer event change, libev twice per iteration). + +- watchers use less memory + (libevent on amd64: 152 bytes, libev: <= 56 bytes). + +- library uses less memory + (libevent allocates large data structures wether used or not, libev + scales all its data structures dynamically). + +- no hardcoded arbitrary limits + (libevent contains an off-by-one bug and sometimes hardcodes a limit of + 32000 fds). + +- libev separates timer, signal and io watchers from each other + (libevent combines them, but with libev you can combine them yourself + by reusing the same callback and still save memory). + +- simpler design, backends are potentially much simpler + (in libevent, backends have to deal with watchers, thus the problems) + (epoll backend in libevent: 366 lines, libev: 90 lines, and more features). + +- libev handles EBADF gracefully by removing the offending fds. + +- doesn't rely on nonportable BSD header files. + +- a event.h compatibility header exists, and can be used to run a wide + range of libevent programs unchanged (such as evdns.c). + +- win32 compatibility for the core parts. + +- the event core library (ev and event layer) compiles and works both as + C and C++. + +whats missing? + +- no event-like priority support at the moment (the ev priorities + are not yet finished and work differently, but you can use idle watchers + to get a similar effect). + +AUTHOR + +libev was written and designed by Marc Lehmann and Emanuele Giaquinta. + +The following people sent in patches or made other noteworthy +contributions (if I forgot to include you, please shout at me, it was an +accident): + +W.C.A. Wijngaards +Christopher Layne +Chris Brody