Performance Tests

 Performance Tests:

Frequently we discuss performance testing without considering the specifics. Multiple types of performance tests can be performed on a system at a very high scale.

The most common types of performance tests are as follow

LATENCY TEST

• It is intended to compute the end to end transaction time.
• The latency of the system is an observable parameter to the management, which tells how long customers have to wait for a transaction to happen. Hence this is one of the important performance tests.
• Avg. value computation is not the right choice, latency is mostly computed in terms of P99.99, P99.9, P99, and P95.

THROUGHPUT TEST

• It defines how many concurrent transactions a system can handle.
• Latency and throughput tests are mostly interrelated.
• Max throughput of the system is measured until the system starts degrading.

LOAD TEST

• It represents a binary question — can the system handle a specific load?
• It is mostly conducted just before the business events e.g. launch in a new country, viral content, and social media events.

STRESS TEST

• It is intended to compute the breaking point of the system and how much spare headroom systems have.

ENDURANCE TEST

• To detect the anomalies in the system if the system runs for an extended duration.
• Many problems in the system are detected only if the system runs for a longer duration e.g. Slow memory leaks, cache population, and memory fragmentation issues.
• It is the most suggested test for the fast response system which cannot tolerate the long length of the stop the world event caused by the full GC.

CAPACITY PLANNING TEST

• To check if the system scales as per the expectations when additional resources are added to the system.

DEGRADATION TESTING

• To check the behavior of the system when it partially fails. It is also known as the partial failure test.
• It is usually done to validate the resiliency of the system. Chaos Monkey by Netflix is one such example to build a truly resilient system.

RULES TO SELECT TESTS

Golden rules that provide useful guidance over which performance test you should perform:

• Identify what you care about and figure out how to measure it.
• Optimize what matters, not what is easy to optimize.
• Play the big points first.

NON FUNCTIONAL REQUIREMENTS

Observables that are important to the management and system.

NFR’s are generally provided as follow by the management:

• Reduce the 95% percentile transaction time by 100ms
• Improve system so that 5x throughput on existing hardware is possible.
• Improve average response time by 30%