In the latest release (Sense/Net 6.1, you can get it here) there are a number of performance improvements. We decided to include a module in the product that helps these kind of development tasks.
Performance counters are well-known tools for measuring the performance of a Windows application or web site. Sense/Net provides several built-in performance counters and lets developers add their own custom performance counters. These can be used to measure the performance of a custom module by writing one line of code.
For more information about counters see this wiki article.