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From Dirk-Willem van Gulik <>
Subject Re: Accept locking test code strangeness
Date Wed, 10 Oct 2001 17:06:47 GMT

On Wed, 10 Oct 2001, Justin Erenkrantz wrote:

> > lack thereof) in the multiple listener case.  They are required to avoid
> > race conditions that can deadlock your server with the 1.3 process/accept
> > model.
> In fact, I bet that is why Sander thought that pthread mutex worked
> on Linux - he didn't have a multiple listener config, so the mutexes
> never get called.

Actually - just to be clear; what we are doing at the OSDL is
systematically trying ALL accept locking mechanims on a 1-16 CPU machine
to get a better idea of the cost of the locking methods.

This was promted by a SunTone certification procedure Covalent's product
(which is directly based on apache) had to go through - where we
discovered that on 8+ CPU machines a (in our opinion) too large amounth of
CPU cycles where solidly spend on locking and inter CPU comm's.

Obviously this is mostly/totally a function of the OS; not of apache.  We
just work on the assumption that Apache would just needs some sort of
accept lock.


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