What is Software Performance Testing & Why it is Required?

What is Performance Testing?

Performance testing is a Non-Functional Testing type in software testing.

Performance testing is performed to determine how a software application or a system performs in terms of responsiveness and stability and reliability under a given workload.

What it Measures?

Performance testing measures the quality attributes of the system, such as speed, scalability, reliability, and resource usage. 

• Speed - Determines whether the application responds quickly enough for the users(SLA)
• Scalability - Determines the maximum user load a software application can handle. This helps to measure the ability of the application to scale with the increasing workload. (AKA Capacity)
• Stability - Determines if the application is stable under a given user load
• Reliability - Determines if the application works reliably without any errors under a load

Why Performance Testing?

1. To confirm and validate SLA(Service Level Agreement) in the requirement.
2. The main goal is not to find bugs but to eliminate performance bottlenecks that could have an impact on the system.
3. To detect what parts or module of the system or workload causes the system to perform slowly.
4. Performance testing can detect what needs to be improved before the application goes to real users.
5. To compare two systems to find which performs better or to check the current application capacity.
6. Mission-critical applications like aircraft control systems, space launch programs, or life-saving medical equipment should be thoroughly performance tested to ensure that they run for a long period without any impact on the functionality.

Let's look at the below examples how large an impact it can have on a software system:

• A 5-minute downtime of Google.com on 19th August 2013 resulted in an estimated loss of $545,000 to the company.
• An Amazon Web Service Outage resulted in an estimated loss of sales worth $1100 per second.