[OT] This feels wrong (pthreads question)

Jason Hall jayce at lug-nut.com
Tue Jan 30 08:30:13 MST 2007

On Monday 29 January 2007 16:29, Daniel C. wrote:
> I thought at first that the processes were threads, but then I thought
> about it and wondered whether I was correct or not.

This can be true, false, and both at the same time, simply depending on your 
apache version and configuration.  As of Apache 2.0 you have had various 
MPM's which you can use, that define this setup.  The default Unix setup is 
the one used in Apache 1.x that is a basic prefork model.  Each 'thread' is 
simply a forked process.  You have a configuration option as to how many it 
will fork ahead of time, how many are in reserve, and up to what point it can 
spawn new processes on demand if needed.

In the goals of flexibility and cross-platform friendliness, several other 
MPM's were added, such as a pure-threading model which increased performance 
in windows, but is usable on unices (no real reason though).  As well as a 
pure threaded, there is a popular worker MPM that is a hybrid model, 
preforking a set number of processes, each with a thread pool of it's own.  
Googling around will find the pros and cons of each of these models, with 
their numerous caveats.


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