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From Cyrille Artho <car...@email.arc.nasa.gov>
Subject Thread safety issues
Date Tue, 10 Sep 2002 15:58:46 GMT
Hi,
as someone who works on multi-threaded problems, but not Apache, I ran 
into your page at
http://httpd.apache.org/docs-2.0/developer/thread_safety.html

I strongly suggest to revise it, because it lacks depth. First of all, 
you probably should start explaining the basic problem in case a 
developer has never used threads: what is a race condition (and what is 
a deadlock), why is it hard to test (because it is scheduling-dependent, 
the scheduling cannot be controlled).

What can be done about it (manual analysis, VisualThreads under Alpha). 
Basically the programmer has to ensure that each access to shared data 
is protected by at least one common lock (the word "common" is important).

When to use apr_atomic_* and apr_thread_mutex_*. How to use them.

Perhaps make a small shell script that parses the ldd output and 
compares each line to a "database" of libraries in it, printing 
problematic libraries.

Maybe you can cover some of these issues by linking to other pages. It 
is important that they are well documented, otherwise people will never 
dare using 2.0 or writing modules for it.

I personally hope 2.0 will be adapted fast, but I know such things take 
time. Good luck, and keep up the good work!
--
Regards,
Cyrille Artho


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