I'm trying to troubleshoot slows requests on a website so I have configured Failed Request Tracing to trigger for requests taking 10 seconds or more. I'm getting logs but though they take 10+ seconds the performance view tab doesn't show where the time is spent. Why is that?
I have the same problem and it seems that IIS Time Taken logs are saved only up-to point when the request exceeds threshold. When I set up tracing based on status code, it will always log all events in .xml file. Try to create trace based on Status code (200) and compare tail of .xml with tail of "Time Taken" .xml and you will see missing part. I guess that it's bug in IIS. I'm using IIS 8.5 on Windows Server 2012 R2. More information is in this article: http://blogs.msdn.com/b/tess/archive/2008/08/19/troubleshooting-a-performance-issue-with-failed-request-tracing-and-appcmd-in-iis7.aspx
来源：https://stackoverflow.com/questions/24416447/iis-failed-request-tracing-performance-view-doesnt-show-time-spent