Google is making Android phones faster, improving battery

Google is working on some behind-the-scenes changes that should make Android phones feel faster while also improving battery life.

Announced by the Android LLVM toolchain team this week, Google is updating the Android kernel with “AutoFDO” – Automatic Feedback-Directed Optimization.

What is that?

In short, your phone has to make “thousands of small decisions” behind the scenes, which end up taking up a considerable portion of CPU usage. AutoFDO changes this by guiding the compiler along the “most common” execution paths, thereby reducing the load. That, in turn, leaves more horsepower for other tasks while also improving battery life by consuming less power.

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Google explains:

During a standard software build, the compiler makes thousands of small decisions, such as whether to inline a function and which branch of a conditional is likely to be taken, based on static code hints. While these heuristics are useful, they don’t always accurately predict code execution during real-world phone usage.

AutoFDO changes this by using real-world execution patterns to guide the compiler. These patterns represent the most common instruction execution paths the code takes during actual use, captured by recording the CPU’s branching history. While this data can be collected from fleet devices, for the kernel we synthesize it in a lab environment using representative workloads, such as running the top 100 most popular apps. We use a sampling profiler to capture this data, identifying which parts of the code are ‘hot’ (frequently used) and which are ‘cold’. When we rebuild the kernel with these profiles, the compiler can make much smarter optimization decisions tailored to actual Android workloads.

In early tests, Google says that it has found this brings real improvements, including 2.1% faster boot time, 4.3% faster “cold” app launch time (when the app was fully closed), and bigger improvements to other metrics that aren’t quite as noticeable by the end user. The guided patterns were built using the 100 most popular apps on smartphones in an effort to simulate real-world use, at which point the patterns were built to optimize the “hot” – frequently used – portions of the code.

Google says that AutoFDO in Android’s kernel will run in a “conservative by default” strategy, leaning on the old ways of doing things if a certain process ends up falling outside of the guided patterns.

These changes are coming to the latest Android kernel versions – android16-6.12 and android15-6.6 – as well as the upcoming android17-6.18 release. The end result, Google says, will translate to “a snappier interface, faster app switching, extended battery life, and an overall more responsive device for the end user.”

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