For rasa Number of Threads issues

Hello,everyone! I found a problem when I used the jmeter software to test the interface.Returned to empty in my custom action(To eliminate external factors).When I increase the thread, the response time will increase.For example: Number of Threads = 2、run time = 30minutes

Number of Threads = 5、run time = 30minutes I tried to increase the Number of threads to 100 running time of 8 hours, and the average response time is about 25 seconds.So,I want to know if rasa has requirements for Number of threads,and how many users can be accessed by rasa at the same time? Best wishes to everyone!