Re: [PATCH Resend] epoll: add EPOLLEXCLUSIVE support
From: Jason Baron
Date: Thu Mar 29 2012 - 14:54:23 EST
On Thu, Mar 29, 2012 at 06:32:22PM +0200, Hagen Paul Pfeifer wrote:
> * Jason Baron | 2012-03-29 11:53:24 [-0400]:
> >I was trying to better understand the use-case, since at least for the
> >test case you posted, 'EPOLLET', already does what you want.
> >Also, the 'EPOLLEXCLUSIVE' flag in your patch addresses multiple threads
> >blocking on *different* epoll fds. However, if multiple threads are
> >blocked on a single epoll fd, they will all be woken even if 'EPOLLEXCLUSIVE'
> >is set. Shouldn't 'EPOLLEXCLUSIVE' affect that case too?
> Hey Jason,
> I just wanted to address the "main use-case" (as implemented in a bunch of
> network server): one listen socket (say 80) is created and a epoll fd is
> created. The listen socket is added to the set and n threads are created
> afterwards. So now you have the situation that one listening socket is added
> to the set and all threads are awoken if a new client connects. This patch
> reduce the useless-all-thread-awoken-overhead by awake only one thread.
But the behavior of the testcase you've supplied is not changed by the
'EPOLLEXCLUSIVE' support. So is this not the right testcase?
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