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From Jeff Trawick <traw...@attglobal.net>
Subject Re: worker MPM Question
Date Sat, 17 Nov 2001 13:27:14 GMT
Ian Holsman <ianh@cnet.com> writes:

> I've been doing some quick performance runs again, and have noticed
> (well.. other people did before me) that the worker MPM tends to
> concentrate all it's work to a few processes leaving
> others doing nothing.

Do you have reason to believe that some process is accepting a
connection when it has no worker available to process it, while some
other process with idle workers isn't ever getting the accept mutex?
(I suppose the size of the queue between listener thread and worker
threads is supposed to avoid this; not sure.)

Since all listener threads for processes whose work queue isn't full
are blocked in a mutex, we're at the mercy of the OS for deciding who
gets it (no guarantee of round-robin).

I guess the potential problem on a system with fewer kernel
dispatchable units than threads (M:N) is that a process with
supposedly idle threads and space in the queue will get a connection,
but there won't be a free kernel dispatchable unit immediately.

But if M=N, then what is the problem with idle processes?

Does this make any sense?

-- 
Jeff Trawick | trawick@attglobal.net | PGP public key at web site:
       http://www.geocities.com/SiliconValley/Park/9289/
             Born in Roswell... married an alien...

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