Google is rolling out an optimized kernel to devices with Android 15 and Android 16, and it was built using a technique called Automatic Feedback-Directed Optimization (AutoFDO). Google engineers loaded test phones up with the 100 most popular Android apps and simulated the kinds of things real users do every day. While that was happening, the engineers used tools to record which parts of code the processor ran constantly and which parts it hardly touched. The result of this work is a kernel that has been compiled using a detailed map of how Android actually gets used in the real world.
Kernel operations account for about 40% of CPU time on Android devices. By using AutoFDO to speed up the kernel build, the development team was able to achieve up to a 26.4% improvement for certain performance benchmarks in a controlled Android 16 test. The team says the gains aren’t just on paper, asserting that they “translate to a snappier interface, faster app switching, extended battery life, and an overall more responsive device for the end user.”
While speed boosts are nice, the most important takeaway for many users will be AutoFDO’s improvement to battery life. Several flagship Android phones have better battery life than the iPhone 17 Pro already, even without this impactful new update. Now, Android devices stand to perform even more efficiently when it comes to energy drain.
How AutoFDO is improving Android’s performance and battery life
Automatic Feedback-Directed Optimization was originally designed to improve warehouse-scale applications for Google. It delivered a mean 10.5% improvement in targeted benchmarks. Further research and application of the technology have made it reliable enough to bring significant and constant improvements to consumer Android devices.
In the Android kernel, the AutoFDO process starts with profile collection — in other words, recording which parts of the kernel code are used most during everyday tasks. From there, rarely-used code gets stripped out, leaving only the parts that matter. The last step is testing, which entails verifying the profile against previous versions to make sure it is consistent with expectations. This three-step pipeline runs continuously to counteract “code drifting” that would otherwise cause the profile to lose effectiveness, ultimately resulting in the aforementioned speed and battery improvements.
Google says AutoFDO has also improved boot times and app launch speeds in other parts of Android, and in the real world, this should translate into more of those all-important battery gains. Needless to say, AutoFDO is a marked improvement to the operating system. It goes to show why skipping software updates is one of the things you should never do on Android — you might be missing out on a major upgrade to your phone’s speed and battery life.
