How to Use JMeter for Performance & Load Testing

Apache JMeter testing tool offers following benefit in Performance Testing

• JMeter can be used to test the performance of both static resources such as JavaScript and HTML, as well as dynamic resources, such as JSP, Servlets, and AJAX.
• JMeter can discover maximum number of concurrent users that your website can handle
• JMeter provides a variety of graphical analyses of performance reports.

JMeter Performance Testing includes: The figure below shows how JMeter load Testing simulates the heavy load: In this tutorial, we are doing a performance analysis of Google.com for 1000 users

Before testing the performance of target web application, we should determine-

• Normal Load: Average number of users visit your website
• Heavy Load: The maximum number of users visit your website
• What is your target in this test?

Here is the roadmap of this practical example

Step 1) Add Thread Group

1. Start JMeter
2. Select Test Plan on the tree
3. Add Thread Group

Right click on the "Test Plan" and add a new thread group: Add -> Threads (Users) -> Thread Group In the Thread Group control panel, enter Thread Properties as follows: The Thread Count and The Loop Counts are different.

Ramp-Up Period tells JMeter how long to delay before starting the next user. For example, if we have 100 users and a 100-second Ramp-Up period, then the delay between starting users would be 1 second (100 seconds /100 users)

Step 2) Adding JMeter elements

Now we determine what JMeter elements in this test. The elements are

• HTTP request Default

This element can be added by right-clicking on the Thread Group and selecting: Add -> Config Element -> HTTP Request Defaults. In the HTTP Request Defaults control panel, enter the Website name under test (http://www.google.com) Right-click on Thread Group and select: Add -> Sampler -> HTTP Request.

In HTTP Request Control Panel, the Path field indicates which URL request you want to send to Google server. For example, if you enter "calendar" in Path field. JMeter will create the URL request http://www.google.com/calendar  to Google server If you keep the Path field blank  JMeter will create the URL request http://www.google.com to Google server.

In this test, you keep the Path field blank to make JMeter create the URL request http://www.google.com to Google server.

Step 3) Adding Graph result

JMeter can show the test result in Graph format.

Right click Test Plan, Add -> Listener -> Graph Results Press the Run button (Ctrl + R) on the Toolbar to start the software testing process. You will see the test result display on Graph in the real time.

The picture below presents a graph of a test plan, where we simulated 100 users who accessed on website www.google.com. At the bottom of the picture, there are the following statistics, represented in colors:

• Black: The total number of current samples sent.
• Blue: The current average of all samples sent.
• Red: The current standard deviation.
• Green: Throughput rate that represents the number of requests per minute the server handled

Let analyze the performance of Google server in below figure.