What are different characteristics of software performance testing?

Software performance is indeed an important part of software engineering and software development plan. It can be defined as the testing carried out to determine the quality and standard of the response and stability of the software system under a certain work load. Sometimes it an also be used to examine other qualitative aspects of the software system like scalability, reliability, security, stress, and resource usage.

In actual, the software performance testing is essentially a part of performance engineering. This is a very crucial testing methodology and is gaining popularity day by day. It is a testing methodology which seeks to raise the standards of the performance factors of the design of the software system. It is also concerned with the architecture of the internal structure of a software system or application.

Performance testing tries to build excellent performance into the architecture and design of the software system before the actual coding of the software application or system. Performance testing consists of many sub testing genres.

Few have been discussed below:

- Stress testing
This testing is done to determine the limits of the capacity of the software application. Basically this is done to check the robustness of the application software. Robustness is checked against heavy loads i.e. above the maximum limit.

- Load testing
This is the simplest of all the testing methods. This testing is usually done to check the behavior of the application or software or program under different amounts of load. Load can either be several users using the same application or the difficulty level or length of the task. Time is set for task completion. The response timing is recorded simultaneously. This test can also be used to test the databases and network servers.

- Spike testing
This testing is carried out by spiking the particular and observing the behavior of the concerned application software under each case that whether it is able to take the load or it fails.

- Endurance testing
As the name suggests the test determines if the application software can sustain a specific load for a certain time. This test also checks out for memory leaks which can lead to application damage. Care is taken for performance degradation. Throughput is checked in the beginning, at the end and at several points of time between the tests. This is done to see if the application continues to behave properly under sustained use or crashes down.

- Isolation testing
This test is basically done to check for the faulty part of the program or the application software.

- Configuration testing
This testing tests the configuration of the application software application. It also checks for the effects of changes in configuration on the software application and its performance.

Before carrying out performance testing some performance goals must be set since performance testing helps in many ways like:
- Tells us whether the application software meets the performance criteria or not.
- It can compare the performance of two application soft wares.
- It can find faulty parts of the program.

There are some considerations that should be kept in mind while carrying out performance testing. They have been discussed below:

- Server response time:
It is the time taken by one part of the application software to respond to the request generated by another part of the application. The best example for this is HTTP.

- Throughput
It can be defined as the highest number of users who use concurrent applications and that is expected to be handled properly by the application.
A high level plan should be developed for performing software performance testing.