Relation between Constant throughput timer, transactions per sec and throughput in summary report

Question

enter image description hereI am setting a test plan where I need to set a load of 15 request per min for my web service. How can I do so?

I tried set up the test plan as below: No. of threads: 20 Ramp up period:10 Duration: 120 seconds Constant throughput timer is set under thread with values: Target throughput: 15 Calculated throughput: All Active threads

Result: Under summary report it showed throughput value as 33.9/min. I am not getting how this exceed 15/min set under constant throughput timer. Also, under transactions per sec graph, the value in intervals touch as 2,3,1,....and 20 in end.

I am not able to understand the relation between constant throughput timer, Throughput under summary report and transactions per sec graph.

Answer 1

It might be the case Constant Throughput Timer is not "precise" enough, given you need to limit JMeter's throughput to 15 requests/minute assuming 20 threads it's better to consider Throughput Shaping Timer which has lower granularity therefore it's being applied immediately and gives exact throughput figures comparing to the Constant Throughput Timer / Precise Throughput Timer.

The relevant configuration would be:

You can install Throughput Shaping Timer plugin using JMeter Plugins Manager: