How Loop count = -1 works in jmeter

Question

Unable to understand how loop count = -1 works in jmeter?

As per my understanding, when Threads = 2 Ramp up time = 2sec Loop count = 2

Delay between the threads = 2/2 = 1sec

then,

At 10:00:00, T1 
             T1
   10:00:01, T2
             T2

Since the loop count is 2, same thread (T1/T2) will be executed concurrently.

This is my current understanding, how will this work when loop count =-1.

According to me only T1 executes, even if the threads > 1.

But in the results, i can see other threads used. Unable to understand.

Answer 1

Loop Count -1 in Thread Group means that all threads will execute samplers forever

Having 2 threads with 2 seconds ramp-up doesn't guarantee concurrency because if underlying Sampler(s) response time is less than 1 second you will run into the situation then T1 has already finished its work and was shut down and T2 hasn't yet been started.

If you want 2 or more threads to execute Sampler(s) at exactly the same moment - consider using Synchronizing Timer

You can also check out Thread Group/thread start and end times using Log Viewer