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From Niklas Edmundsson <>
Subject Re: event mpm and mod_status
Date Tue, 15 Jan 2013 10:36:41 GMT
On Sat, 12 Jan 2013, Stefan Fritsch wrote:

> On Thursday 10 January 2013, Niklas Edmundsson wrote:
>> To reiterate back to the event mpm / mod_status integration, are
>> there any work in progress on implementing a more verbose status
>> display for the event mpm? I'm thinking of something that can show
>> all requests currently being processed like we have today for
>> prefork/worker. The current "thread status" thingie is probably
>> interesting too, but more from a developer/server diag point of
>> view.


> I am not aware of anyone working on this.


> I agree that mod_socache may be a bit heavy-weight for this, but one
> would need to test that.

My guess is that it's the one-big-lock requirement that bogs this 
down for high request/s rates, but for us it might be good enough.

> There is also mod_slotmem_shm, but AFAICS
> that requires to know the size in advance. So one would have to
> allocate AsyncRequestWorkerFactor times (max number of threads) slots
> to have one slot per connection.

I'll investigate a bit when time allows. Part of the problem is to 
find something useful to use as an identifier/index, process/thread is 
obviously not enough.

> This would still not give the full picture, because with pipelining,
> there can be several (5 or 6, I think) requests active on one
> connection: zero or one being processed by a worker and the rest doing
> write completion. I am not sure how much effort one should put into
> displaying that correctly in mod_status, though.

Given that all file delivery will be done by write completion I think 
we'll want this to be rather accurate, at least for the connections 
doing write completion (think a server being overloaded serving DVD 
images, it gets easier to diagnose if you can easily figure out the 

  Niklas Edmundsson, Admin @ {acc,hpc2n}      |
  If it's useless, it will have to be documented.

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