Author :
Andy Pan
Date :
2024-04-17 10:36:47
Hash :6074d558 Message :Avoid calling read(2) on eventfd on each event-loop wakeup
Register the eventfd with EPOLLET to enable edge-triggered notification
where we don't need to read the data from the eventfd for every wakeup
event.
When the eventfd counter reaches the maximum value of the unsigned 64-bit,
we rewind the counter and retry again. This optimization saves one system
call on each event-loop wakeup, which eliminates the extra latency for epoll
as the EVFILT_USER filter does for the kqueue.
Andy Pan