How to use Load Generator Calculator?

In this article, you are going to learn about what is Load Generator Calculator and how to calculate the number of virtual users that can run on load generator machine with step by step screenshots. Quite many of you might have heard about this utility. This Load Generator Calculator was introduced in HP LoadRunner 12 package. This utility will help you to calculate how many virtual users that can run on a Load Generator machine for the specified script.

Purpose of Load Generator Calculator

The main intend of this calculator is to calculate the number of virtual users that can run on load generator machine for the particular script and by specifying the memory and CPU parameters.

How to launch Load Generator Calculator?

Load Generator Calculator is hidden in the following path: C:\Program Files (x86)\HP\LoadRunner\bin\HP.LR.LG.Calculator.exe

Below is the snapshot of it.

Load Generator Calculator
Load Generator Calculator

How to use Load Generator Calculator?

There are three fields you need to fill in before you hit Start Estimation button.

  1. VuGen Script
  2. IP addresses or host names
  3. CPU and/or Memory

Click on the highlighted button to specify the script path as shown below.

Specify Script Path
Specify Script Path

Next, you need to specify the IP addresses or host names as shown below. You can enter multiple IP addresses as well by pressing the enter key.

Specify IP addresses
Specify IP addresses

Third step is, you need to specify the CPU and/or Memory limits (in bytes) by double clicking on the checkbox.

Specify threshold limits
Specify threshold limits

In this example, I checked only CPU threshold at 70%. Now, hit Start Estimation button. Once you hit that button, the calculator will start connecting the LG machines and displays the log instantly.

Runtime Updates
Runtime Updates

Once the estimation is done, it will display the results in Results multi-text box as shown below. In this example, it is displaying the error message as expected. But if you use the tool in your organization network, if you have right setup, it will give you the calculated output.

Output Log
Output Log

You can save the log in text format by clicking on Save log button. The output varies, the protocols used in the script, business processes involved in the script and the resources such as CPU and Memory available in LG machines.

Your turn: please give it a shot and let me know your experience of using this calculator.

2 thoughts on “How to use Load Generator Calculator?”

  1. Hello Naveen,
    Thanks for the post. I tried LG Calculator and had a questions.

    How relevant is the Vuser estimation for LG? I tried calculating the Vuser per LG for SAPGUI Vuser and Webscript Vuser.

    When i calculated the SAPGUI Vuser by old fashion which is running the script and identifying the resource footprint, we estimate about 20SAP GUI Vusers /LG and ~200 Web Vusers/LG

    But when i calculated Vuser/LG through LR new feature, i get 75 SAPGUI Vuser per LG and 15 Web Vuser per LG.

    I am not sure how true is the information we get from LG calculation feature .

    Let me know your comments.

    Reply
  2. Hi,

    I have tried using LG calculator from the above mentioned utility, but I am seeing an error as – Failed, reason: Monitor de-initialization error: The internal object for machine is invalid ( initialization error ).

    Can you please help me on the same, I have given the IP address of the LG and controller tried with IP’s of multiple machines but none of them were successful

    Reply

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