Epoll(Linux Programmer's Manual)
epoll-I/OeventnotificationfacilityTheepollAPIperformsasimilartasktopoll(2):monitoringmultiplefiledescriptorstoseeifI/Oispossibleonanyofthem.TheepollAPIcanbeusedeitherasanedge-triggeredoralevel-triggeredinterfaceandscaleswelltolargenumbersofwatchedfiledescriptors.