Query on response time
Hi,
I am doing load testing on web application. I have created web test and I am calling that test in my load test.
Load pattern: Constant
When I am running the test with 500 users response time was 4.8 seconds
When I am running the test with 750 users response time was 3.7 seconds
1. When users are increasing, the response time also should increase right. Because the load is more in this second case the response time should also be more right. But test results were showing response time was less in second case (3.7 seconds for 750 users) compared to first case (4.8 seconds for 500 users). How it is possible? where test went wrong?
Thanks,
Shankar
[2524 byte] By [
ShankarK] at [2007-12-22]
Hi,
I have restarted the machine and executed the second scenarios (with 750 users). Now response time was 5.2 seconds.
Why these results are varying for same scenario? I am calling same web test and same load test at all times. Application was running fine. There is no problem with application (Like sever was down. Etc)
Why results are not consistent using VSTS Load test tool? This is surprising.
Thanks,
Shankar
The results probably aren't consistent because some caching had occurred after running the 500 user test that enabled the first 750 user test to run faster. The web server probably had everything JIT compiled, required data in memory, pages cached, and plenty of threads spun up when you hit it with the first batch of 750 users. The fact that rebooting bumped the reponse time right back up to slightly above what you saw with 500 users seems pretty normal.
That said, there are always going to be variances in load tests such as when garbage collection occurs on the server (and client to some degree), network congestion, and other processes running on the client and server. The idea is that for a sufficiently long load test run under the same conditions (web server cold vs. warm) these variances should be reduced to minor noise in the data.
Josh
