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Intro:

Using JMeter 5.4.1, I have generated the HTML dashboard report for a test with 2 Concurrency thread groups, both having the tstFeedback function configured as such ${__tstFeedback(ThroughputShapingTimerOut,1,1000,10)} along with a Throughput Shaping timer which increases the target load by 21 RPS every one minute. The Threads have some sort of synchronization using an InterThreadCommunication plugin because I need to pass information from one thread to the other.

Issue description:

One Thread group does not need all the 1000 Threads to generate the specified load because it is faster at a given time so only 22 Threads are active at that point in time, however, the Active Threads Over Time chart displays the line at the same level as the Thread which had 1000 active threads at that time. My expectation was that it should be lower (visually is should be much further apart from the other thread group line). Upon hovering over result, it seems to display the correct number of threads, but the scale on the left side is around the 1000 count.

Here are some screenshots about what I mean: enter image description here enter image description here

This seems to me as an issue with the graphical representation of the active threads over time chart. Can someone confirm that my assumption is correct?

JustNatural
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1 Answers1

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No, it's just a chart which visualizes the number of active threads (grpThreads column of the .jtl results file)

You can generate the same chart using MS Excel or equivalent

enter image description here

and/or use Active Threads Over Time listener (can be installed as a part of 3 Basic Graphs bundle using JMeter Plugins Manager)

If you're using inter-thread communication plugin and some threads are "waiting" for the data and not doing anything - they will still be displayed as "active" because in JMeter world "active" means a thread that has been "started", but "active" doesn't necessarily mean that the thread is doing anything as it may "sleep" due to a Timer

Dmitri T
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  • Ok, I can understand that I have a different expectation of what "Active" means, but in the first screenshot I posted, when hovering over that specific dot on the yellow line it says that at that point in time "there were 22 active threads", yet the line is drawn at the same level with the 1000 Threads on the "Y axis". Does that dot have a different definition of active threads than the drawn line itself? I am not sure I am clear enough with my question , please let me know if I should rephrase. – JustNatural Dec 22 '21 at 12:23