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Date: Wed, 01 Mar 2006 09:55:38 -0500
From: Greg Ames <gregames@apache.org>
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To: dev@httpd.apache.org
Subject: Re: Event MPM accept() handling
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Saju Pillai wrote:

> I can understand why serializing apr_pollset_poll() & accept() for the 
> listener threads doesn't make sense in the event-mpm.   A quick look
> through the code leaves me confused about the following ...
 >
>  It looks like all the listener threads epoll() simultaenously on the 
> listener sockets + their private set of sockets added to the pollset by 
> workers. 

looks like you are correct.

originally there was a separate event thread for everything but new connections and the 
listener thread's accept serialization was the same as worker's.  then it seemed like a 
good idea to merge the listener and event threads, and it only supported a single worker 
process briefly.  since there was only one merged listener/event thread in the whole 
server there was nothing to serialize at that time.  then a few of us grumbled about what 
happens if some 3rd party module seg faults or leaks memory and we went back to multiple 
worker processes.

>   Will apr_pollset_poll() return "success" to each listener if a 
> new connection arrives on a main listener socket ? If so won't each
> listener attempt to accept() the new connection ?

I think so, but I'm not a fancy poll expert.  Paul?

then the question is how bad is it?

Greg


Greg