High Performance Android Apps

Chapter 6. CPU and CPU Performance

In the preceding chapters, we’ve looked at battery, UI, and memory management performance, and how optimizing the way these function will reduce crashes and speed up the performance of your app. As we continue our journey to high performance Android apps in this chapter, we’ll cover an essential part of the Android device, the CPU. The CPU is the brain of the device, and because the CPU processes all of your code to create your app, it is another vital piece of the puzzle to optimize.

In fact, chipset vendors work constantly to improve the performance of their chips, while taking into account battery drain and heat concerns. Modern Android devices have shown great performance strides in speed while also ensuring efficiency.

In the last few years, quad, octo, and deca core CPUs are becoming more common in the market. Unlike your computer (where every CPU is the same, and can be interchanged for any computation), these ARM-based mobile chipsets feature different CPUs for different tasks. ARM calls this chipset design big.LITTLE, and it is a good descriptor for how they work. When a small background task is run (like checking email), a lower-powered, more efficient CPU will be tasked with the job. When users watch videos or play games, the high performance cores are fired up. By relegating small tasks to the LITTLE processors, and only using the big CPUs for high-power tasks, the device saves energy. The great thing as a developer is that this is ...