Evaluating Performance Problems

Performance evaluation for most software products is a very scientific process. First, we determine the maximum/minimum supported performance metrics, such as the allowed memory usage, acceptable CPU consumption, and the number of concurrent users. Next, we perform load testing against the application in scenarios with a version of the application built for the target platform, and test it while gathering instrumentation data. Once this data is collected, we analyze and search it for performance bottlenecks. If problems are discovered, we complete a Root Cause Analysis (RCA), and then make changes in the configuration or application code to fix the issue and repeat it.

Although game development is a very artistic process, it is still exceptionally technical. Our game should have a target audience in mind, which can tell us what hardware limitations...

Gathering profiling data using the Unity Profiler

The Unity Profiler is built into the Unity Editor itself and provides an expedient way of narrowing down our search for performance bottlenecks by generating usage and statistics reports on a multitude of Unity3D subsystems during runtime. The different subsystems for which it can gather data are listed as follows:

• CPU consumption (per-major subsystem)
• Basic and detailed rendering and GPU information
• Runtime memory allocations and overall consumption
• Audio source/data usage
• Physics engine (2D and 3D) usage
• Network messaging and operation usage
• Video playback usage
• Basic and detailed user interface performance
• Global Illumination (GI) statistics

There are generally two approaches to making use of a profiling tool: instrumentation and benchmarking (although, admittedly, the two terms are often used interchangeably).

Instrumentation...

Best approaches to performance analysis

Good coding practices and project asset management often make finding the root cause of a performance issue relatively simple, at which point the only real problem is figuring out how to improve the code. For instance, if the method only processes a single gigantic for loop, then it will be a pretty safe assumption that the problem is either with how many iterations the loop is performing, whether or not the loop is causing cache misses by reading memory in a non-sequential fashion, how much work is done in each iteration, or how much work it takes to prepare for the next iteration.

Of course, whether we're working individually or in a group setting, a lot of our code is not always written in the cleanest way possible, and we should expect to have to profile some poor coding work from time to time. Sometimes, we are forced to implement...

Final thoughts on profiling and analysis

One way of thinking about performance optimization is the act of stripping away unnecessary tasks that waste valuable resources. We can do the same and maximize our own productivity by minimizing any wasted effort. Effective use of the tools we have at our disposal is of paramount importance. It would serve us well to optimize our own workflow by remaining aware of some best practices and techniques.

Most, if not all, advice for using any kind of data-gathering tool properly can be summarized into three different strategies:

• Understanding the tool
• Reducing noise
• Focusing on the issue

Understanding the Profiler

The Profiler is a well-designed and intuitive tool, so understanding the...

Summary

You learned a great deal throughout this chapter on how to detect and analyze performance issues within your applications. You learned about many of the Profiler's features and secrets, explored a variety of tactics to investigate performance issues with a more hands-on approach, and have been introduced to a variety of different tips and strategies to follow. You can use these to improve your productivity immensely, so long as you appreciate the wisdom behind them and remember to exploit them when the situation makes it possible.

This chapter has introduced us to the tips, tactics, and strategies we need in order to identify a performance issue that requires improvement. In the remaining chapters, we will explore methods on how to fix issues and improve performance whenever possible. So, give yourself a pat on the back for getting through the boring part first. We...