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From Brian Akins <>
Subject Re: Keepalives
Date Fri, 17 Jun 2005 15:12:38 GMT
William A. Rowe, Jr. wrote:
> Yes it makes sense.  But I'd encourage you to consider dropping that
> keepalive time and see if the problem isn't significantly mitigated.

It is mitigated somewhat, but we still hit maxclients without our "hack" 
in place.

> Right now, it does take cycles to walk the
> scoreboard to determine the number in a given state (and this is
> somewhat fuzzy since values are flipping as you walk along the
> list of workers.)  

I know the worker MPM, for example, keeps a count of idle workers 
internally.  Maybe just an mpm query to retrieve that value would be 
good?  all MPM's keep track of this in some fashion because they all 
know when maxclients is reached.

> Adding an indexed list of 'counts' would be
> very lightweight, and one atomic increment and decrement per state
> change.  This would probably be more efficient than walking the
> entire list.

Sounds good.  Of course, when changing from on state to another you 
would always have to decrement the previous state and increment the new 
one.  The way the core seems to be now, that would require some careful 
examination of the code to ensure all the state changes were covered.

Brian Akins
Lead Systems Engineer
CNN Internet Technologies

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