[Zope-dev] Zope.pipeline proposal

[Shane Hathaway]

Hanno Schlichting wrote:
> What's the overhead of a WSGI middleware? Is the overhead cost in the
> same order of magnitude as a simple function call with a return value or
> is there something inherently more complex going on?

A WSGI middleware app is simply a callable thing that calls the next 
app, so the overhead is literally the same as a simple function call. 
There won't be security proxies or any other such thing getting in the way.

>>From my current experience I usually classify things into the groups of:
> 
> 1. attribute access
> 2. function calls
> 3. adapter lookups
> 
> Going from one of these groups into the next one has a very noticeable
> performance cost involved, if used on the critical path of the application.

The current publisher is chock full of function calls and adapter 
lookups along the critical path.  I expect the zope.pipeline project to 
open everyone's eyes about just how much we're already doing in the 
critical path.  I think much of it is frequently not needed at all.

Shane