Howto track performance issues?

[JulienM]

I am trying to improve performance on a prestashop site with an addons theme and a dozen of custom modules.

While the total user time is almost acceptable, I can see the first page "server waiting time" is very high (more than 1 second). 

I activated profiling, and I see a 1100ms load time which matches what I can see on firebug.

Database does not seem to be an issue, total "time spent querying" is around 30ms.

I tried to install the entire site on a powerful dedicated server and did not see real improvements.

 

Is there any way to have a profiling module per module and hook by hook?

Also I see a very high config time (250ms) and initContent (600ms), display is around 200ms. How can I figure out what these times match and how to reduce them?

 

Trying to track source code line by line, I figured that price calculation is 10-20ms, and this happens 10 times per page, which is a lot in total (200ms to get product prices!!!)

 

My goal is to get a total load time around 300ms, which is what we currently have with our ecommerce site.

 

An advice appreciated.