Performance testing determines how responsive and stable a system is under different workloads. It tests for speed, scalability, stability, and ensures a positive user experience. Types of performance testing include load testing to evaluate behavior under expected loads, and stress testing to find upper capacity limits. Key metrics measured are response time, throughput, and resource utilization. Performance testing involves planning test goals, methodology, implementation, validation of results, and interpreting results. Common tools used for performance testing are JMeter, LoadRunner, and Webload.

1. Performance Testing
By Tharinda Liyanage

2. What is Performance Testing
• Testing to determine how a system performs
in terms of responsiveness and stability under
a particular workload.
• It can also serve to investigate
scalability, reliability and resource usage.

3. Why we do performance testing
• To demonstrate that the system meets performance criteria.
• To compare two systems to find which performs better.
• To measure what parts of the system or workload causes the
system to perform badly.
– Speed - Does the application respond quickly enough for the intended
users?
– Scalability – Will the application handle the expected user load and
beyond? (AKA Capacity)
– Stability – Is the application stable under expected and unexpected
user loads? (AKA Robustness)
– Confidence – Are you sure that users will have a positive experience
on go-live day?

4. Types of testing
• Load Testing
– behavior of the system under a specific expected
load
• Concurrency
• Speed/Throughput
• Stress Testing
– the upper limits of capacity within the system
• Scalability/Stability

5. Types of testing
• Benchmark testing
• Compare competitive product
• Check performance with previous builds

6. What we measure
• Response time
– User concerns
• Throughput
– Business concerns
• Resource utilizations
– System concerns

7. Phases of Performance Testing
• Project assessment
– Goals/Scoping: “What do you want to achieve?”
• Methodology/Planning
– “How do you plan to achieve it?”
• Implementation/Execution
– “Doing what you planned”
• Validation/Evaluation
– “Did you achieve your goals?”
• Results/Interpretation
– “What does the output of the testing mean?”

8. Tools
• Free/Open source tools • Other useful tools
– JMeter • Httpwatch
• Commercial tools • YSlow
– Load Runner
– Webload