Concurrent Thread and Ultimate Thread Group and Performance Bench mark

Question

While understanding concept of Concurrent thread and ultimate thread group, i am confused to understand result of summary/aggregate report while running concurrent thread or ultimate thread group .For example if i have 200 user and ramp up time 60 sec then i didn't see all sampler request as 200 sample after completing execution successfully but only few sampler request have 200 sample. when i use normal thread group then i always got thread count same for each sampler request after completing execution .

for realistic load testing with more user , could you please suggest me which thread group should prefer.

Could you please provide valuable guidance with some valuable link/book and also share me standard performance bench mark criteria or key parameter detail while doing load testing.(if any bench load parameter value does not meet standard then we can say that there is a performance issue)

Thanks for giving valuable time in advance.

Thanks

amit

Answer 1

This is due to the fact that:

1. Your application response time is too high
2. Your test duration is too low

For example I can see response times > 80 seconds:

it means that if a single virtual user has cumulative response time for 2 samplers > 160 seconds and the test duration is 120 seconds it will not be able to execute all the requests. Just increase your test duration to be i.e. 10 minutes and you should see more virtual users capable of executing all the Samplers you defined in the test plan.

Also given first user is capable of executing all the requests successfully and in time it looks like that your application gets overloaded hence cannot respond fast enough when the number of concurrent users reaches some "critical threshold", you can add listeners like Active Threads Over Time and Response Times vs Threads, this way you will be able to correlate increasing load with the increasing response time.

If also makes sense to collect:

1. Baseline health metrics of your application (CPU, RAM, Network, Disk usage, etc.), it can be done using JMeter PerfMon Plugin.
2. Lower level details like slowest methods, largest objects, heaviest database queries, etc. This form of information can be obtained using profiling tools specific to your application programming language(s).