VSTS-response time measurement accuracy?

response time measurement accuracy? Was this post helpful ?

results are quite different when benchmark between vsts2005 loadtest and loadrunner, wonder what exactlyvsts and how it measured? and if there are benchmark whitpaper from Microsoft or somewhere? Thanks!
performance and capacity

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Answer Re: response time measurement accuracy? Was this post helpful ?

In the VSTS results, are you looking at "Avg. Response Time" for requests, or "Avg. Page Time"? Are the values greater or less than the response times reported by LoadRunner?

An important thing to understand in the VSTS load test results is the difference between “Avg. Response Time” for requests and “Avg. Page Time” for pages.

Consider a web page (home.aspx) that contains 10 images. When a Web test that contains a request to home.aspx runs, there will be 11 HTTP requests sent (1 for home.aspx and 1 for each of the 10 images) just as there would be with a browswer (ignoring caching for simplicity). The round trip times for receive each of these 11 individual requests is recorded. The averages for each URL are shown in the "Requests" table in the load test results (and can also be added to the graphs). The average request response time across all URLs is reported in the performance counter "Avg. Response Time" with the instance name "_Total" which is included in the default graph created by VSTS.

However, you may be more interested in the "Avg. Page Time". The page time is the time measured from the time a page request is sent until all bytes for the page and all of the dependent requests (for images and such) are received.

So, going back to the example, if the HTTP response to the request to get home.aspx takes 3.4 seconds and the time to get the 10 embedded images is 0.1 seconds each, the load test results would show:
In the Requests table: Request Response Time home.aspx 3.4 image1.gif 0.1 image2.gif 0.1 etc.

In the Pages table: Page Page Time home.aspx 4.4

On the default graph: Counter Instance Category Avg Avg. Response Time _Total LoadTest:Request 0.4

If you add Page Time to the graph: Avg. Page Time _Total LoadTestage 4.4
The Avg. Response Time for requests is much lower than the Avg. Page Time because there are many fast requests to images.
Other recommended reading:
"Monitoring and Analyzing a Load Test Result": http://msdn2.microsoft.com/en-us/library/aa730850(vs.80).aspx
"Advanced Load Testing Features of Visual Studio Team System": http://msdn2.microsoft.com/en-us/teamsystem/aa718897.aspx
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Re: response time measurement accuracy? Was this post helpful ?

Thank you very much Bill!I think if I put BeginTransaction() and EndTransaction(), it will be no confusing.
performance and capacity