When the SharePoint application you are working on has unsatisfactory response times how do you pinpoint the causes and in which sequence? So far I have not yet found any open source or commercial profiling tools specific for the SharePoint segment, so any pointer to tools or best practices will be appreciated.
PS. I am aware of the profiling options for the web parts but I am looking for something that covers the entire application.
Best Answer
My advice is to look at the following:
Data Layer Check and see if your database is chugging along, and what requests are taking a lot of time. 90% of everything you see in SharePoint is stored in the database somewhere. Run SQL Profiler for a few hours and examine your logs.
Site Collections I have found in SharePoint that the deeper you arrange your sites and site collections, the further that performance degrades. This is purely anecdotal, so take it with a grain of salt.
Other than that, I don't know of many SharePoint profiling tools. My experience with SharePoint has pushed my away from heavy customization jobs, and towards using more functionality OOTB. I rarely recommend using SharePoint as an application platform.
Good Luck!