Our app has started intermittently crashing several times a day. The w3wp process has normal memory use of 450 MBs and the cpu usually fluctuates between 10-50%. When it starts exhibiting problems, the cpu will range from 50-100% (often sitting right around 100%) and the memory use will increase to over 2 GBs. Then a new w3wp process kicks off and the out of control one winds down.
My question is how can we figure out what is causing this?
We tried the ANTS Performance Profiler and captured one of these out of control app restarts. However, it seems that all of the significant cpu time is spent in IIS / ASP.NET overhead. None of the heavy hitters relate to our actual code. For example, below are the top few heaviest hitters with respect to cpu percentage:
PipelineRuntime.ProcessRequestNotificationHelper (20%), HttpApplication.ExecuteStep (15%), IIS7WorkerRequest.ReadEntityCoreSync (12%), Unmanaged code (7%), SNIReadSyncOverAsync (6%), OutOfProcSessionStateStore.MakeRequest (3%), Page.ProcessRequestMain (2%), and it keeps dropping off from there to miniscule amount of cpu usage.
These are our specs: asp.net 4.5 app hosted in IIS 7.5 on Windows Server 2008 with 6 GBs of RAM and an Intel Xeon CPU E5450 @ 3.00GHz 2.83 GHz (2 processors).
Thanks in advance!
Kyle