[Zope] Re: one zope instance per cpu

[Tres Seaver]

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Pat McNamee wrote:
>> Generally, the rule-of-thumb for scaling Zope on a multi-CPU box is to
>> run an appserver instance per CPU, each talking to a shared storage...
> 
> I came across the preceeding post while googling for info about the
> one zope per cpu question.
> 
> First, when you say one zope instance per cpu, do you count a quad-core
> cpu as four cpus?

Four:  the idea is to split up the processes so that their threads make
best use of the available CPUs.  Python's global interpreter lock makes
using more than one CPU within a single process problematic.

> Also, I've been (unsuccessfully) searching all over for an answer to
> the question: if you create one zope instance per cpu each talking
> to a shared zeo instance, how do the instances know about the cpus?
> Does each instance automagically use a separate cpu or what?

Modern linux kernels will tend to migrate all the processes to separate
CPUs (in steady state).

> I thank you in advance for your reply, and I hope I'm not being
> rude by emailing you instead of the Zope list. If this is rude
> please tell me and I'll post to the list.

CC'ing the list does leave the conversation open, and makes future
searches likelier to show the "whole picture".


Tres.
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Tres Seaver          +1 540-429-0999          tseaver at palladion.com
Palladion Software   "Excellence by Design"    http://palladion.com
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