What is the ramp-up period in jmeter?

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I ran a test plan with 5 users for a total of 20 seconds and what I am not able to understand is what ramp-up period is in actual. Does it means that each user will get 4 seconds or 20 seconds will be used in total for 5 users?

If case 1 is true(4 second for each user) then the first thread should be completed in 4 seconds but it took 6 seconds to complete it and still the result is passed and next user gets executed? This gets much confusing. I need to clear my doubt as I am not able to find any answers from all the inputs that are available here

2 Answers

As per JMeter Thread Group Documentation:

Ramp-up Period

How long JMeter should take to get all the threads started. If there are 10 threads and a ramp-up time of 100 seconds, then each thread will begin 10 seconds after the previous thread started, for a total time of 100 seconds to get the test fully up to speed.

You have 5 users

  • if you set ramp-up period to 0 - all 5 users will start at once
  • if you set ramp-up period to 5 - JMeter will start with 1 user and will add an extra 1 user each second
  • if you set ramp-up period to 10 - JMeter will start with 1 user and will add an extra 1 user each 2 seconds
  • etc.

Once user is started it starts executing Samplers upside down (or according to Logic Controllers) when there are no more samplers to execute or loops to iterate - the thread is being shut down.

Check out JMeter Ramp-Up - The Ultimate Guide article for more information on configuring users arrival rate.


You might also be interested in Ultimate Thread Group which makes workload definition easier, moreover you will have a chart representing anticipated load. You can install Ultimate Thread Group using JMeter Plugins Manager

If you want threads not to effect test expected time then use instead Thread group's Loop Count as the number of repeatitions you need.

If you want/must use threads calculate ramp period time as

  (test expected time + 1 second) * number of threads
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