% RT verification time

Question

When monitoring performance counters during the .NET web application load test, the critical default threshold of 10 was constantly exceeded for a counter called "% time in RT checks."

Why is it bad to spend a lot of time checking runtime?
What can this say about our application? How to improve it?

Answer 1

This threshold does not necessarily indicate poor performance (depending on what you are doing, 10% of the processing time may not be very good!).

There is another related counter: "Total Runtime checks". This counter displays the actual number of runtime checks (it is documented here ). If the value in this counter is small, the likelihood that you have no problem. If it is high (or growing rapidly at certain points in your application), you may have a problem that needs to be studied.

These "runtime checks" are code access security checks that run when your code requests a specific CAS permission from the runtime. If your code is complex or runs under limited trust, you may find that you are making a lot of requests and that you can rebuild your code to optimize them. However, I would be sure that this is a problem before looking too deeply, as this is not always an easy optimization.