[Zope] zope performance issues

[Matt Hamilton]

>> Thanks for the link Chris. How about scaling across
>>SMP systems???.
> 
> 
> Just use multiple Zope processes, one for each processor, all talking to
> the same ZEO server.  For best performance, "bind" each Zope process to
> a single processor (the process for doing so differs across operating
> systems).

Trevor,
   Just to elaborate this a bit more, this is an issue to do with the 
global interpreter lock in python.  It is an issue with any interpreter 
or virtual machine.  Java has the same problems.  I wrote a paper a few 
years ago on performance of Zope/Python on multi-processor Solaris boxes:

http://zope.org/Members/glpb/solaris

In it there is references to Java people (specifically BEA Weblogic 
people) finding that they were encountering the same thread locking 
issues as I was discovering.  Since then Sun have changed their default 
threading libraries to be the 'alternative' ones discussed in that paper. :)

I think most java app servers internally start multiple JVM processes 
and balance the load across them (I know mod_jk or mod_jserv does). 
This is that same as what you can achieve with multiple ZEO clients, one 
for each process, and is accepted as a 'standard' process within the 
Zope community on multi-processor systems.

-Matt

-- 
Matt Hamilton                                       matth at netsight.co.uk
Netsight Internet Solutions, Ltd.        Business Vision on the Internet
http://www.netsight.co.uk                             +44 (0)117 9090901
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