I am trying to profile a specific page of my ASP.NET site to optimize memory usage, but the nature of .NET as a Garbage Collected language is making it tough to get a true picture of what how memory is used and released in the program.
Is there a perfmon counter or other method for profiling that will allow me to see not only how much memory is allocated, but also how much has been released by the program and is just waiting for garbage collection?
The best way that I have been able to profile memory is to use ANTS Profiler from RedGate. You can view a snapshot, what stage of the lifecycle it is in and more. Including actual object values.
Actually nothing in the machine really knows what is waiting for garbage collection: garbage collection is precisely the process of figuring that out and releasing the memory corresponding to dead objects. At best, the GC will have that information only on some very specific instants in its cycle. The detection and release parts are often interleaved (this depends on the GC technology) so it is possible that the GC never has a full count of what could be freed.
For most GC, obtaining such an information is computationally expensive. If you are ready to spend a bit of CPU time on it (it will not be transparent to the application) then you can use GC.Collect() to force the GC to run, immediately followed by a call to GC.GetTotalMemory() to know how much memory has survived the GC. Note that forcing the GC could induce a noticeable pause, and may also decrease overall performance.
This is the "homemade" method; for a more serious analysis, try a dedicated profiler.