Imagine a test with multiple test cases that will run over multiple load generators. This article will go over how to count how many Virtual Users (VUs) will execute each test case in a DMTC.


This article refers to multi-test case tests, but the same principals apply to tests with test case groups

Rule of thumb

Before a test starts, StresStimulus allocates VUs between load generators and test cases in the following order:

  1. Allocate VUs between load generators according to each generator's mix weight.
  2. Within each load generator, allocate VUs between each test case according to each test case's mix weight. The test case mix weight on the load generator is called Gen Mix Weight.


Starting from v5.2 each test case can have a different mix weight for every load generator. This gives more flexibility for distributing VUs in a distributed test.

Determining mix weights

Let's take a test that will have a maximum load of 1000 VUs between 4 test cases running across 3 load generators (named East, West, Local). Below is an example of desired VU distributions between the test cases.

Test CaseDesired VUsPercent
View Store35035
Search Store47547.5
Place Order12512.5
Return Item505

Click the Configure VU distribution > By Load Agent - TC... button to bring up the VU configuration dialog

Distribute VUs between load agents

According to the rule of thumb, first, the 1000 VUs are distributed between load agents. In the dialog, select the All Load Agents node and modify the Mix Weight column on the left. The VU Distribution column shows the actual number of VUs that will be executed on the agent. 

Load Agent Mix WeightPercentNumber of VUs


When the sum of the mix weights equal sum of VUs to distribute, then the individual mix weights equal the individual VU distribution.


Distribute VUs between test cases

Now that the VUs have been distributed between the load agents, the test case distribution can be configured on each agent individually.

East (500 VUs)West (300 VUs)Local (200 VUs)
Test CaseGen Mix WeightPercentNumber of VUs
View Store15030150
Search Store30060300
Place Order25525
Return Item25525

500 VUs
Test CaseGen Mix WeightPercentNumber of VUs
View Store15050150
Search Store15050150
Place Order000
Return Item000

300 VUs
Test CaseGen Mix WeightPercentNumber of VUs
View Store502550
Search Store2512.525
Place Order10050100
Return Item2512.525

200 VUs

Select an agent node to modify the test case mix weights

East (500 VUs)West (300 VUs)Local (200 VUs)


In the above example, the test cases Place Order and Return Item will not run on the West since their mix weights are 0 for that load agent.

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