I've been given the task for creating a performance model for a legacy product. The product is about 10 years old and has never had any performance requirements or performance models before. Generally whats happened in the past is a customer will complain that a particular feature is slow or they are not getting the throughput that they want/need and the developers will investigate and see if any more performance can be squeezed out the code for the feature.
Since the product doesn't have any hard measurements and metrics for past versions I fell all I can do is create baselines for the current version and go from there. Other developers sometimes notice that memory usage is really high and ask why. Also, I am new to the product so I don't know all the feature points (which there are hundreds to thousands) and the performance cost of running each.
The program is an ASP.NET/.NET 2.0 webapp on IIS 6. I've started looking into performance counters and the CLR Profiler to start getting measurements. I've also read the following docs:
So my question is: How can I create a performance model for a legacy product that I am new too and hasn't had a performance model/requirement in the past?