Is it good, sample time increasing gradually along with increase in number of users

Question

In Starting of script sample time is less and then it starts increasing as the load increasing, is it the correct way to do load testing for website? Please help, which is the correct way to do load testing for website

Answer 1

Not really, in ideal world response time should remain the same as the load increases like:

1. 1 user - response time 1 second - throughput 1 request per second
2. 100 users - response time 1 second - throughput 100 requests per second
3. 200 users - response time 1 second - throughput 200 requests per second
4. etc.

The situation when response time doesn't start increasing is called saturation point - it is the maximum throughput your application can support.

The situation when response time starts increasing as you start more threads (virtual users) is known as the bottleneck and the question is: whether performance is still acceptable for that number of users that is defined in NFR and/or SLA. If yes - you're good to go, if not - you need to report this issue (it would be beneficial if you could try to determine reason for this)

The correct way of load testing the website is simulating end users activity as close as possible including workload model. Remember to increase the load gradually, this way you will be able to correlate increasing load with metrics like response time, throughput, number of errors. It is also good to decrease the load gradually as well to see whether your website recovers when the load gets back to normal/zero.