Why does WCF Service Hosted In IIS report a higher response time than the Call Duration? RRS feed

  • Question

  • I have a WCF Service (.Net framework 4.0 ) hosted in IIS 7. The service makes database calls. Both the Application and Database are installed on separate boxes ( 4C/4GB each).

    I have a constant load of 1000 concurrent requests generated from a single Visual Studio Client.

    The Performance Counters measured are as follows,

    Arrival Rate @ HTTP.SYS : ~1100

    ASP.NET Requests / Second : ~1100

    WCF Calls Per Second : ~1100

    The above counters point that the at no stage the requests getting queued. So I haven’t changed any of the ASP.NET settings (Process model – autoconfig = true, maxConcurrentRequestPerCPU=5000, HTTP.SYS queue = 1000)

    But I see the processing time increasing.

    WCF Call Duration (ms) : 280

    ASP.NET Request Execution Time (ms) : 540

    Total Request Latency (ms) : 920 ( Measured at the VS Web Test Client )

    With the “Requests Queued” counter of ASP.NET always showing zero, I’m trying to find out what makes the ASP.NET Execution double when compared to actual WCF call duration.

    Are the responses getting queued due to any I/O bottleneck?

    Are there any counters that needed to looked into other than the counters mentioned above.

    Any inputs would be appreciated.

    Thank you.


    Thursday, July 31, 2014 12:31 PM

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