io

epoll
eventfd for inter-thread comms
epollfd for socked comms

#include <sys/epoll.h>

int epoll_create (int size)

A successful call to epoll_create() instantiates a new epoll context, and returns a file descriptor associated with the instance.
The size parameter is a hint to the kernel about the number of file descriptors that are going to be monitored; it is not the maximum number. Passing in a good approximation will result in better performance

once done, release the resources with close(fd)

int epoll_ctl (int epfd,                int op,
                int fd,
                struct epoll_event *event);

epoll_ctl() system call can be used to add file descriptors to and remove file descriptors from a given epoll context


 struct epoll_event
{
         __u32 events; /* events */
         union
        {
                 void *ptr;
                 int fd;
                 __u32 u32;
                 __u64 u64;
         } data;
  };





https://www.kernel.org/doc/man-pages/online/pages/man2/eventfd.2.html
http://stackoverflow.com/search?q=epoll
http://linux.derkeiler.com/Mailing-Lists/Kernel/2006-03/msg00084.html
http://linux.die.net/man/2/epoll_ctl
http://en.wikipedia.org/wiki/Epoll
http://www.kegel.com/c10k.html
http://bulk.fefe.de/scalability/
http://pl.atyp.us/content/tech/servers.html
http://www.citi.umich.edu/projects/linux-scalability/reports/accept.html
http://www.devshed.com/c/a/BrainDump/Linux-Files-and-the-Event-Poll-Interface/