JMeter Constant Throughput Timer doesn't pause until all threads have started

Question

I am using a Constant Throughput Timer with "Calculate throughput based on: all active threads in current thread group" selected. When I specify 50 threads on the Thread Group and a throughput of 1 sample per minute, I see 50 samples go through immediately and then 1 sample per minute after that. It seems that the Constant Throughput Timer is not being applied to the first sample for each thread.

Does anyone know what I am doing wrong? Here is my test setup.

Here are the results of letting it run for a few seconds.

I expect it to only run one time when it starts, since the throughput is 1.0. After it has launched every thread, it only runs once per minute.

Answer 1

I think you're hitting this bug:

• https://bz.apache.org/bugzilla/show_bug.cgi?id=51480

There is a old incomplete patch for it that you may want to try.

You may want to try this plugin:

• https://jmeter-plugins.org/wiki/ThroughputShapingTimer/

Answer 2

Ok, I figured out a workaround. Since the problem is with the first pass through the test plan, I just used a counter and created an "If" controller to identify and skip the first pass through. Not the prettiest answer but it works around the bug.

Counter:

"If" Controller:

Hope this helps someone!