#Load testing with data driven web test - how load test take that data?

I have a simple query 

If My web Test is data driven with 10# of username & passwords  and then I add that web Test to load test. 

with both patterns Step load (5 to 500) and Constant load (of 50). 

How load test hit/take those 10# rows of  username & passwords and how can I verify that all these have been entered while load testing.