WCF Serice - Performance testing with jMeter
===

I have developed a RESTful WCF service (WebHttpBinding). I ran a performance test using jMeter. The test plan contained one operation in the service, which will be called in 100 concurrent threads. However, I noticed that after running the test, the first 20 to 30 threads are taking considerable amount of time to get the response (say 10-15 seconds) and then all the other remaining threads will complete their execution in 2-3 seconds. It seems to me as if the first few threads are blocking the threads that reach the server after them.

My service has the below configurations:


[ServiceBehavior(InstanceContextMode = InstanceContextMode.PerCall, ConcurrencyMode = ConcurrencyMode.Multiple)]

And also,

<serviceThrottling maxConcurrentCalls="300" maxConcurrentSessions="300"/>



Cold someone please give some pointers as to what is causing this initial delay?








