Performance Testing

“Performance testing is the process by which software is tested to determine the current system performance. This process aims to gather information about current performance, but places no value judgements on the findings".

Performance Tests are tests that determine an end to end timing of various time-critical business processes and transactions under a particular workload.
It can demonstrate that the system meets performance criteria
It can compare two systems to find which performs better
It can measure what parts of the system or workload cause the system to perform badly

Performance criteria:

Most important for iterative testing.
Baseline (single user) for initial basis of comparison and ‘best
case’.
Benchmark (15-25% of expected user load) determines actual
state at loads expected to meet requirements

Performance measures:

Speed
Scalability
Stability
Confidence

Performance scenario:
The test scenario is based on the use of application, design and other constraints.