Benchmarking Zend Framework with a plugin

I have created this plugin to benchmark the performance of my Zend Framework Project

http://pastebin.com/HD9MpRfR

One odd thing that happens is that sometimes the generated values are negative,

Unit: Microseconds 
Routing: 0.0013879999999999 
Dispatch : -0.477942 
Dispatch Loop: -0.470018 
To开发者_运维百科tal : -0.430279 

Why is this?

Your code is calling microtime(). I think you need to call it like this: microtime(true). According to the PHP documentation:

If used and set to TRUE, microtime() will return a float instead
of a string, as described in the return values section below. 

So, you are substracting strings every time. It might lead to strange results.

Also, check the returned *Start and *End values, maybe there is some problem in the logic of your plugin (I didn't review it in detail). An alternative technique could be to store these values in Zend_Registry instead of member variables. Maybe your plugin is being called several times, for startup and shutdown (this would reset the values of the member variables).

Hope that helps,