perfmon shows instances = 0

Apr 27, 2010 at 6:23 PM

Hi All,

I've done some extensive testing with this tool and it works great.

Something is a little odd though... I've been playing around with the throttling values and also changing the ConcurrencyMode and InstanceContextMode.

In Performance Monitor I check the "Instances" for my WCF Service.

The instances show up correctly. Example: If I set the InstanceContextMode to "Single", perfmon always shows 1 instance. If I set the InstanceContextMode to "PerSession", then perfmon will show that as many instances as I have configured in the throttling values (MaxConcurrentSessions or MaxConcurrentInstances). But if I set the InstanceContextMode to "PerCall" and ConcurrencyMode is "Multiple", perfmon shows random instances (random per load test). Sometimes, if I run the tests for a short while (eg. 2 minutes), the perfmon shows 0 instances (even though WCF calls were made). How is this even possible? Can WCF calls be made without any instances? Also, from my random instance results, it looks like new instances are spawned to cope with the WCF calls. Can anyone explain this instancing behavior?