SOME OF THE BASIC TERMS USED IN PERFORMANCE ENGINEERING

1. Bottleneck

A bottleneck is a point in an application where congestion and delay occur, slowing down the processing of requests and causing users to experience unacceptable service delays.
2. Capacity

The capacity of a system is the total workload it can handle without violating predetermined key performance acceptance criteria.
3. Capacity test

A capacity test complements load testing by determining your server’s ultimate failure point, whereas load testing monitors results at various levels of load and traffic patterns. You perform capacity testing in conjunction with capacity planning, which you use to plan for future growth, such as an increased user base or increased volume of data. For example, to accommodate future loads, you need to know how many additional resources (such as processor capacity, memory usage, disk capacity, or network bandwidth) are necessary to support future usage levels. Capacity testing helps you to identify a scaling strategy in order to determine whether you should scale up or scale out.
4. Continuous Integration

Continuous Integration is a Software Engineering term describing a process that completely rebuilds and tests an application frequently. Generally it takes the form of a server process or Daemon that monitors a file system or version control system (such as CVS) system for changes and automatically runs the build process (e.g. a make script or Ant-style build script) and then runs test scripts. Other approaches use nightly or hourly builds.
5. Endurance test

An endurance test is a type of performance test focused on determining or validating performance characteristics of the product under test when subjected to workload models and load volumes anticipated during production operations over an extended period of time. Endurance testing is a subset of load testing.
6. Horizontal scaling

Adding more computer systems (servers) to the environment. See also: Vertical scaling
7. Instrumentation

Inserting (either statically or dynamically) code around program events in order to capture performance data. See also: Profiling

8. Latency

In general terms, a time delay between the moment something is initiated, and the moment one of its effects begins. In the realm of software performance, latency is often referred to in the contexts of server latency, network latency and disk latency.
9. Load Test

A performance test focused on determining or validating performance characteristics of the product under test when subjected to workload models and load volumes anticipated during production operations
10. Performance

Performance refers to information regarding your application’s response times, throughput, and resource utilization levels.
11. Performance test

A performance test is a technical investigation done to determine or validate the speed, scalability, and/or stability characteristics of the product under test. Performance testing is the superset containing all other subcategories of performance testing.
12. Profiling

The insertion of tools into program code that traces events captures metrics as the program is running. Examples of java profiling tools are JProbe, JXInsight and dynaTrace. Also see: Instrumentation
13. Response time

Response time is the amount of time that it takes for a server to respond to a request.
14. Saturation

Saturation refers to the point at which a resource has reached full utilization.
15. Scalability

Scalability refers to the ability to handle additional workload, without adversely affecting performance, by adding resources such as CPU, memory, and storage capacity.
16. SLA

Service Level Agreement. In the context of performance testing, it is often the required level of performance (response time), availability (up time) or both.
17. Spike test

A spike test is a type of performance test focused on determining or validating performance characteristics of the product under test when subjected to workload models and load volumes that repeatedly increase beyond anticipated production operations for short periods of time. Spike testing is a subset of stress testing.
18. Stress test

A stress test is a type of performance test designed to evaluate an application’s behavior when it is pushed beyond normal or peak load conditions. The goal of stress testing is to reveal application bugs that surface only under high load conditions. These bugs can include such things as synchronization issues, race conditions, and memory leaks. Stress testing enables you to identify your application’s weak points, and shows how the application behaves under extreme load conditions.
19. Throughput

Throughput is the number of units of work that can be handled per unit of time; for instance, requests per second, calls per day, hits per second, reports per year, etc.
20. Utilization

In the context of performance testing, utilization is the percentage of time that a resource is busy servicing user requests. The remaining percentage of time is considered idle time.
21. Vertical scaling

Adding more (or faster) CPUs within the same computer system. See also: Horizontal scaling