Load Runner and Architecture

What is Load Runner?

Load Runner is one the most used performance tool in the market. The tool was with HP still 2016 and it was bought by microforces Company. Load Runner will support all the protocol.

And it is very user friendly compared to any other performance testing tool. It works on a principal of simulating Virtual Users on the subject application. These Virtual Users also termed as VUsers, replicate client's requests and expect a corresponding response to passing a transaction.

Architecture of Load Runner and Components

Architecture Diagram- Load Runner

Most important components in the Load runner are:-


VUGen or Virtual User Generator is an interface to record the end user action. Script will be used to simulate the end each user action as real user on the application. Using single Vugen script we can simulate multiple user with different credential on the application. Tester can parametrize and use the same script by  passing different values to the application.

VUGen can be used record and simulate following processes:-

  • Online Booking
  • Customer Care Application
  • Mobile Application
  • SAP Application


Controller/Performance Center

Controller or performance center is most important component in Load Runner because once a VUser script is finalized, then the script is uploaded into controller. Controller is the one which will simulate the load on the application.

Most important steps used to simulate the load on the application using controller:-

  • Type of scenario can be selected in the controller that is goal oriented scenario or basic scenario.
  • Uploading of the scripts into scenario
  • Number of  Vuser for each script and the total number of Vuser for the scenario.
  • Number of load generator for the scenario.
  • Calculation of pacing for each script.
  • Calculation of Ramp up that is duration for all the users to be running on the application.
  • Duration of the test.
  • Calculation of Ramp down that is duration for all the users to be logging out of the application.


Load Generator

Load generator is the important component which is used to inject the load on the application. Most importantly assigning of number of  load generator depends upon the protocol selected,number of scripts and number of lines in the scripts because each VUsers will be using resources like memory and CPU. So the best practice is to assign the controller separate and load generator separate for the scenario.


Analysis is the last component of the load runner. Once the execution of the scenario is completed analysis component will be used to display the results collected by the controller. It will also display the graphs for analyzing the execution.

Some of the important graphs used to analyse the result are :

  • Hits per second.
  • Throughput.
  • Running the VUsers.
  • Average response time.
  • Transaction response time.
  • Error rate.
  • Total pass/fail rate.


Leave a Reply

Your email address will not be published. Required fields are marked *