High Level Introduction to Load Testing and JMeter

1. Load Testing & JMeter

2. What is Load Testing?
• Load testing is the process of putting demand
on a system or device and measuring its
response
• Load testing is performed to determine a
system’s behavior under both normal and
anticipated peak load conditions
• Not to find functional bugs

3. User User User
App
3
Normal Use - Few Concurrent
User User

4. User User User User User User User User User User User User User User User
User User
App
4
Spike Use - Many Concurrent

5. User User User User User User User User User User User User User User User
User User
App
5
Spike Use - Many Concurrent

6. Load Testing
Key goals:
 Can app support expected concurrent users?
 How the key functionalities are performing?
 Speed - does the system respond quickly enough
 Capacity - is the infrastructure sized adequately
 Stability - does the system behave correctly under load
 At what load does the app break?
Steps:
 Identify primary user paths
 Identify expected concurrent users
Both now and down the road
 Set up virtual users to hit the app
 Run the test
 Analyze the results

7. Why do load tests fail?
 Ignoring the client processing time
 Scripts not checking for valid responses
 Poor workload modeling
 Poor test data
 Bad Load Test Environments
 Assuming perfect users
 Issues with Load generation box
 Internet Bandwidth

8. Load Testing Approaches
Open Source Tools:
Jmeter
AB ( Apache Bench)
Http_Load
The Grinder
Seige
Commercial Tools:
LoadRunner
WebLoad
Silk Performer

9. Advantages with JMeter
Easy to install and use:
Free!
Java — most platforms
GUI vs. command line
Just download and run!
Feature Rich:
Record from browser
Read test data from files
Add logic, variables & functions
Run a test from multiple machines
Test many protocols, not just HTTP

10. Installing & Running JMeter
1. Download from http://jakarta.apache.org/jmeter
2. Unzip (path with no spaces preferred)
3. Go to "bin" directory
4. Run appropriate file
a. Windows: Double-click jmeter.bat
b. Unix/Mac: Run ./jmeter from command line

11. Your Tests vs Jmeter Features
1. Send/Receive
Request/response
2. Check if you are in correct
page.
3. Parse the response and get
required value.
4. Simulate user Think Time.
5. Conditional statements
6. I want to configure my server
url, data etc
7. View & Analyze the results
1. Sampler
2. Assertion
3. Pre/Post Processors
4. Timers
5. Logic Controllers
6. Config Elements
7. Listeners

12. Let’s build a small JMeter script
No parameterization:
 Go to Login page
 Enter user details
 Go to Home page.
Parameterize the test:
 Use Http Request Defaults feature
 Read data from variables and CSV file.

13. Recording scripts in Jmeter
Try Http Proxy Server in JMeter:
 Change browser proxy settings to Jmeter ( localhost,
8080)
 Start Jmeter with Proxy:
 Jmeter.bat -H ProxyServerName -P PortNumber
 Work Bench -> Add ->Non Test Elements-> Http Proxy
Server
 Navigate to the website
 Everything gets recorded.
 Delete unnecessary entries.

14. Limitations of JMeter
 Can't run embedded Javascript, Flash, etc.
 But ... use recording to capture those requests
 Limited by your computer's network connection
 You may have to work with IT to optimize
 1 computer limited to about ~300 concurrent users
 But... use multiple slave computers to handle more
 Reports are a bit lacking
 But... save results and import into Excel, etc.

15. What else need to be picked up?
For Advanced Jmeter Scripting:
 Regular Expressions
 Java ( to use in Bean Shell scripting)

16. Reference
http://jakarta.apache.org/jmeter
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17. Questions?