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I have a question about concurrent user in Jmeter.

If i use setting like this, is that means in first sec 500 thread will hit concurrently?

Then after the first hit, is the threads will repeatedly hit every minute?

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Antoni
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2 Answers2

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It means that JMeter will start 500 threads and will keep them running for 20 minutes.

It doesn't mean that the threads will "repeatedly hit every minute"

All JMeter threads are independent, once started each thread (virtual user) starts executing Samplers upside down. When there are no more loops to iterate or samplers to execute (or test duration is exceeded) the thread is being shut down.

So in your case 500 threads will be repeatedly executing Samplers without any delay (as long as you're not using Timers anywhere) for 20 minutes.

The actual concurrency (number of requests per second) mainly depends on the nature of your test plan and your application response time, it can be checked using i.e. Transactions per Second listener

Dmitri T
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  • hmmm, how about the samples, i'm still confused about the request result, can i said the concurrent test is success when the first 500 request is clear? or when all of the request of the thread within 20 minutes with no error? – Antoni Oct 05 '21 at 05:35
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The preview graph in Concurrency Thread Group is useful to understand how it works.

The preview graph reacts immediately to changes in the fields, showing you the planned concurrency schedule.

Target Concurrency: Number of threads available at the end of the ramp-up period.

**Hold Target Rate Time **: Duration of the test after the ramp-up period. Duration of the test execution with the Target Concurrency

You have not set the ramp-up settings. Hence, JMeter will create 500 tests as the test is started and will run the test for 20 minutes.

Note: It is advisable to set a ramp-up to avoid

  1. Unbearable load to the JMeter client machine (load agent) as the test is started
  2. Unrealistic, sudden load to the target server
Janesh Kodikara
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