[Zope] zope performance issues

Dieter Maurer dieter at handshake.de
Wed May 19 17:25:08 EDT 2004

Trevor Warren wrote at 2004-5-18 22:31 -0700:
> ...
> So this means if i have a Single CPU system, the max
>i can get from Zope multithreaded towards handling 100
>diff threads simultaenously would be really meagre as
>compared to any other application server architectured
>to handle multiple threads simultaenously.

Python's threading model is good for *single* CPU systems.
It usually cannot fully use the power of a *multi* processor

The reason for this: Python uses reference counting
for primary "garbage" detection. Reference count fields
are a global resource and require protection.
Reference count updates are very frequent.
Therefore, it is more efficient (at least on a single CPU system)
to protect large sequences of Python code by a lock
(the so called Global Interpreter Lock (GIL)) than
lock locally for every reference count update.

> Does this esplain the 30TPS as compared to the 100+
>TPS for the simple short circuit(no sql) tests
>conducted on my SMP system here at the labs???.

You can use my "ZopeProfiler" product to find out where the time
is spent. Be warned, profiling drastically slows Zope down.
You do it only to find out the bottlenecks.



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