Using variables in JMeter to generate incremental load

Question

I need to perform an incremental load test using Jmeter. Expected behaviour will look like this: 1st iteration - 10 threads 2nd iteration - 20 threads 3rd iteration - 30 threads etc

I tried use variables in Counter: set Exported Variable Name as "currentThreads", and Counter was placed in the same ThreadsGroup. So value of "Number of Threads" in Thread Properties looks like ${__P(currentThreads)}.
But whole load came in loop and constantly repeated 1 thread at a time.

Is there any proper way to do that?

Thread Group Properties Counter Parameters

Answer 1

The number of threads in the Thread Group is fixed and being evaluated/applied when the test starts.

As of JMeter 5.6.2 your requirement cannot be implemented, if you know how long does "iteration" take you can consider playing with ramp-up period and/or pacing