Re: [users@httpd] How Apache manages all its children - Add More Info

[jayaram.g@xxxxxxx]

Hi,

I just tested with a use case which is having some bug in one of my components after modifying the mod_echo module. My finding is that if one thread execution is having a bug it kills all other threads also( I have atransaction in one thread. So all transactions are in trouble). But Apache recovers in about 30 seconds.

Also suppose you want to utilize 100% of CPU. If it is a prefork model it is possible for you to grab majority of the OS attention to your Server. But in a single process model is it possible that the Apache process uses 100% CPU if load is there with multiple threads?

In Solaris I have attained 100% utilization of boxes with multiple processes.Please correct if I am wrong.

Jayaram Ganapathy

"William A. Rowe, Jr." <wrowe@xxxxxxxxxxxxx> 08/14/2006 08:27 MST Please respond to users@xxxxxxxxxxxxxxxx	To	users@xxxxxxxxxxxxxxxx
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	Subject	Re: [users@httpd] How Apache manages all its children - Add More Info

jayaram.g@xxxxxxx wrote:
>
> I wonder if anybody has tried Windows prefork for Apache 2.2.2.

The issue is the lack-of-fork in the Win32 API.  It's supported at the ntdll
layer, meaning that all the win32-ism's such as their thread-local storage
model don't survive the fork() at all.  For pure NT kernel code it would be
fine, for blended code (even the clib uses the Win32 API) it's very quirky.

> Prefork model adds to the stability I feel.

For buggy modules you are absolutely right, it disrupts only the connection
which caused the instability - and requests which don't trigger the bugs
continue to work fine.

> I am not sure if code in one thread corrupts the heap what will happen?

Same as in worker (for every thread within one process)

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