Spike Testing is a type of performance assessment that examines how the system behaves when the load is significantly increased on the system. Using the Synchronizing Timer in JMeter, you may perform spike testing. The threads are clogged by synchronising the timer until a certain number of threads are blocked, then releasing them all at once, resulting in a significant sudden load.

JMeter offers you two options to carry out spike testing :

Use the JMeter Ultimate Thread Group : This strategy will necessitate advance planning. Using the Ultimate Thread Group, the tester can perform many ramp-ups and ramp-downs in a single test. These could be gradual or more abrupt. For our purposes, you could introduce a spike during the test, for example, after 10 minutes of slow ramp-up and then stable load, ramp up to 10X in 10 seconds, then ramp down to the previous load level after 1 minute. The disadvantage of this method is that you won't be able to regulate concurrency during the test run. You won't be able to predict when the spike will occur.

Use JMeter Properties : This method will provide you with the most choice and flexibility. Determine how many threads you'll run at the start of the test, as well as when you'll want to create spikes dynamically. Use JMeter Properties for the number of threads, then use Real-Time Control to change the Properties while the test is executing.