Constant Throughput Timer is not working as expected in Jmeter

Question

The Constant Throughput Timer does not seem to be doing what it should.

I am using it as a way to ensure x number of requests per second is made across a specified duration.

I set it to 180.0 (meaning 3 requests per second) and then specify the Threadlife time to be 60. But when I run the test with Number of Threads set to 10, I see that the request are being sent out 10 each second. I was expecting it to be sent out 3 req/sec. It seems the value I provided for Constant Throughput Timer is not having any effect.

Is this a case of not configuring it properly? Or how do I achieve what I want?

Answer 1

Constant Throughput Timer acts precise enough on minute level so expect your number of requests applied from 2nd minute and onwards.

If you want the throughput applied from the very beginning of your test you have the following options:

1. Use longer ramp-up period in Thread Group
2. Use Precise Throughput Timer
3. Use Throughput Shaping Timer