Why use an event cache with epoll_wait?

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Published on 2012-11-20T16:57:27Z Indexed on 2012/11/20 16:59 UTC
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Question: epoll man page has some pointers when using epoll with an 'event cache'. But, why would you need to maintain an event cahce at all - Isn't this the same as what epoll is supposed to be doing?

Is it to avoid making multiple epoll_wait calls which might be slower than managing the events in user space?
Is it to implement a custom 'priority' scheme over the cached events?

Background: I'm trying to understand the strengths/shortcomings of epoll and its applicability to different situations

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