How to become an exceptional Performance Engineer

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Whenever I think of performance engineering, I am reminded of Amazon’s CEO Jeff Bezos’ statement, “Focusing on the customer makes a company more resilient.” Any company which follows this consumer-focused approach has a performance engineering domain in it, though in varying capacity and form.

The connection is simple. More and more businesses are becoming web-based, so they are interacting with their customers digitally. In such a scenario, if they have to provide exceptional customer experience, they have to build resilient, stable, user-centric and high performing web-systems and applications. And to do that, they need performance engineering.

What is Performance Engineering?

Let me explain performance engineering with an example. Suppose, your team is building an online shopping portal. The developers will build a system that allows people to access products and buy them. They will ensure that the entire transaction is smooth, uncomplicated for the user and can be done quickly.

Now imagine that to promote the portal, you do a flash sale, and 1000 users come on the platform and start doing transactions simultaneously. And your system, under this load, starts performing slower, a lot of transactions fail and your users are dejected. This will directly affect your brand image, customer loyalty, and revenue.


How about we fix this before such a situation occurs? That is exactly what performance engineering entails. A performance engineer would essentially take into account such scenarios and conduct load tests and check the system’s performance in the development phase itself. Load tests check the behavior of your system in particular situations. A ‘load’ is a possible scenario that can affect the system, for instance, sale offers or peak times. If the system is able to handle the load, it will check if it is scalable. If the system is unable to handle it, they will analyze the result, find the possible bottleneck by checking the code and try to rectify it.

So, for the above example, a performance engineer would have tested the system for 100 transactions at a time, then 500, and then 1000 and would have even gone up to one hundred thousand.

Hence, performance engineering ensures crash-free operation of a system, software or application. Using processes and systematic techniques, practices, and activities, a performance engineer ensures that the performance requirements are met during the development cycle.

However, this is not a blanket role. It would vary with your field of operation. The work of a performance engineer working on a web application will be a lot different than that of a database performance engineer or that of a streaming performance engineer. For each of these, your “load” would vary but your goal is the same, ensuring that your system is resilient enough to shoulder that load.

Before I dive deeper into the role of a performance engineer, I’d like to clarify the difference between a performance tester and a performance engineer. (Yes, they are not the same!)

Performance Tester versus Performance Engineer

Well, many people think that 2-3 years of experience as a performance tester can easily land you a performance engineering job. Well, no. It is a long journey, which requires much more knowledge than what a tester has.

A performance tester would have testing knowledge and would know about performance analysis and performance monitoring concepts across different applications. They would essentially conduct a “load test” to check the performance, stability, and scalability of a system, and produce reports to share with the developer to work on. Their work ends here. But this is not the case for a performance engineer.

A performance engineer will look for the root cause of the performance issue, work towards finding a possible solution for it and then tune and optimize the system to sort the said issue until the performance parameters are met.

Simply put, performance testing can be considered as a part of performance engineering but not as the same thing.

Roles and Responsibilities of a Performance Engineer

Designing Effective Tests

As a performance engineer, your first task is to design an effective test to check the system. I found this checklist on Dzone that is really helpful for designing tests:

  • Identify your goals, requirements, desires, workload model and your stakeholders.
  • Understand how to test concurrency, arrival rates, and scheduling.
  • Understand the roles of scalability, capacity, and reliability as quality attributes and requirements.
  • Understand how to setup/create test data and data management.

Scripting, Running Tests and Interpreting Results

There are several performance testing tools available in the market. But you would have to work with different languages based on the tool you use. For instance, you’d have to build your testing in C and Javascript while working with Microfocus Loadrunner. Similarly, you’d script in Java and Javascript for Apache JMeter. Once your test is ready, you’d run that test on your system. Make sure you use consistent metrics while running these tests or else your results would be inaccurate. Finally, you will interpret those results. In this, you’d have to figure out what the bottlenecks are and where they are occurring. For that, you would have to read results and analyze graphs that your performance testing tool has produced and draw conclusions.

Fine Tuning And Performance Optimisation

Once you know what the bottleneck is and where it is occurring, you would have to find a solution to overcome it to enhance the performance of the system you are testing. (Something a performance tester won’t do!) Your task is to ensure that the system/application is optimized to the level where it works optimally at the maximum load possible. Of course, you can seek aid from a developer (backend, frontend or full-stack) working on the project to figure this out. But as a performance engineer, you’d have to be involved actively in this fine-tuning and optimization process.

There are four major skills/attributes that differentiate an exceptional performance engineer from an average one.

Proves that their load results are scalable

If you are a good performance engineer, you will not serve a half-cooked meal. First of all, take all possibilities into account. For instance, take the example of the same online shopping portal. If you are considering a load test for 1000 simultaneous transactions, consider it for both scenarios wherein the transactions are happening for different products or when it is happening for the same product. If your portal does a launch sale for an exclusive product that is available for a limited period, you may have too many people trying to buy it at the same time. Ask yourself if your system could withstand that load?

Proves that their load results are sustainable

Not just this, you should also consider whether your results are sustainable over a defined period of time. The system should operate without crashing. It is often recommended that a load test runs for 30 mins. While thirty minutes will be enough to detect most new performance changes as they are introduced, in order to make these tests legitimate, it is necessary to prove they can run for at least two hours at the same load. These time durations may vary for different programs/systems/applications.

Uses Benchmarks

A benchmark essentially is a point of reference based on which you can compare and assess the performance of your system. It is a set standard against which you can check the quality of your product/application/system. For some systems, like databases, standard benchmarks are readily available for you to test on. As a performance engineer, you must be aware of the performance benchmarks in your field/domain. For example, you’d find benchmarks for testing firewalls, databases, and end-to-end IT systems. The most commonly used benchmarking frameworks are Benchmark Framework 2.0 & TechEmpower.

Understands User Behavior

If you don’t have an understanding of user reactions in different situations, you cannot design an effective load test. A good performance engineer knows their user demographics, understands their key behavior and knows how the user would interact with the system. While it is impossible to predict user behavior entirely, for instance, a sale may result in 100,000 transactions per hour to barely 100 per hour, you should check user statistics, analyze user activity and conduct and prepare your system for optimum usage.

All in all, besides strong technical skills, as a performance engineer, you must always be far-sighted. You must be able to see beyond what meets the eye and catch what others might miss. The role, invariably, requires a lot of technical expertise. But it also requires non-technical skills like problem-solving, attention-to-detail and insightfulness.

About the Author

Sandeep Deshmukh, PhD

Dr Sandeep Deshmukh is the founder and CEO at Workship. He holds a  PhD from IIT Bombay, and has worked in Big Data, Hadoop ecosystem, Distributed Systems, AI/ML, etc for 12+ yrs. He has been an Engineering Manager at DataTorrent and Data Scientist with Reliance Industries.