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From Ryan Bloom <>
Subject AIX bindprocess call
Date Mon, 08 Feb 1999 15:15:33 GMT

On AIX, we currently make a bindprocess call, to unbind our current
process from any one processor.  The idea, is that if all of our processes
are using the same processos, we are competing for resources, and this is
a performance hit.

The AIX OS developers here at IBM have proposed a patch that modifies this 
call to allow the user to choose to bind to a specific processor. They say
that on a SMP machine this fine-tuning can give a performance boost. Their
argument is that if the I/O all goes through one processor, the registers
are more likely to be setup properly, and we will see an overall
performance increase by not unbinding our processes.  Their patch uses a
command line option that is only good on AIX that allows the user to
target a specific processor for the kernel threads for all Apache

The default will still use the same code, but this gives performance
conscious administrators the chance to fine-tune things as much as

The bindprocessor call just binds the kernel threads to a specific
processor, so the user-level code can still use any available processor.
By allowing users to configure which processor their kernel-threads use, a
power AIX administrator can target different processors for different
tasks and see an overall performance increase.

We could also change their patch to be a config option in the config files
if that makes more sense and follows Apache's style a bit closer.

Should I generate the patch, or do we want to ignore this?


Ryan Bloom
4205 S Miami Blvd	
RTP, NC 27709		It's a beautiful sight to see good dancers 
			doing simple steps.  It's a painful sight to
			see beginners doing complicated patterns.	

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