In Load Runner help center is said about "Running a Vuser as a Process or Thread":

Alternatively, if you run each Vuser as a thread, the Controller launches only one instance of the driver program (such as mdrv.exe), for every 50 Vusers (by default).

How to change quantity of Vusers that run per one instance of the driver program?

1 Answer 1


To change maximum number of threads running per process you need to:

  1. Go to LoadRunner installation folder C:\Program Files (x86)\HP\LoadRunner\dat\protocols
  2. Find .lrp file that is corresponding to the protocol you use to create VuGen Script. In my case it was Java_protocols.lrp file for the protocol Java Record Replay.
  3. Edit it: paste MaxThreadPerProcess=10 after [Vugen]. Or edit this variable if it already exists.
  4. HP LoadRunner Controller should be restarted so that changes could take effect.

You need to find the best ratio Vusers(Threads)/Process to use resources of your test machine the best way. From my experiments I've found that one mdrv.exe process can efficiently work with usage not more than 600-700MB of RAM.

N.B.: VuGen script should be set to run Vuser as a thread.

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