bind enable epool

各个系统上的高效的 multiplex 方法，BSD 有 kqueu，Linux 有 epoll, Solaris 有 /dev/poll。此处 "高效" 是相对传统的 select/poll 说的。

一 : 
Kqueue is a scalable event notification interface that first appeared in FreeBSD 4.1 [...] Some other operating systems which traditionally only supported select(2) and poll(2) also currently provide more efficient polling alternatives, such as epoll(7) on Linux and /dev/poll(4) on Solaris.
二 bind 的 configure --help:
--enable-kqueue use BSD kqueue when available [default=yes] --enable-epoll use Linux epoll when available [default=auto] --enable-devpoll use /dev/poll when available [default=yes]
三 源代码 bind-version/lib/isc/unix/socket.c:
/*%  * Choose the most preferable multiplex method.  */ #ifdef ISC_PLATFORM_HAVEKQUEUE #define USE_KQUEUE #elif defined (ISC_PLATFORM_HAVEEPOLL) #define USE_EPOLL #elif defined (ISC_PLATFORM_HAVEDEVPOLL) #define USE_DEVPOLL typedef struct { unsigned int want_read : 1, want_write : 1; } pollinfo_t; #else #define USE_SELECT #endif /* ISC_PLATFORM_HAVEKQUEUE */转:http://blog.zhangsen.org/2010/10/various-multiplex-methods.html