Thread: Smartphones model - CPU [information collection]

Why UX files from 32-bit skins don't work in 64-bit skins. Architecture:

The evolution of Android architecture from version 9 to 16 represents a transition from a hybrid, legacy-burdened system to a streamlined, 64-bit-first environment optimized for modern hardware.
Architectural Evolution Stages
-Android 9–12 (The Transition Era)
Support: Full compatibility for both 64-bit and 32-bit apps.
Focus: Google mandated 64-bit versions for Play Store apps in 2019. However, the OS still had to load two sets of system libraries (32-bit and 64-bit) into RAM simultaneously, increasing memory overhead and complexity.
-Android 13–14 (The 64-bit Breakout)
Support: Native 64-bit-only support began appearing on flagship hardware.
Focus: Devices like the Pixel 7 launched as 64-bit-only. Removing 32-bit support freed up ~150MB of RAM by eliminating the 32-bit Zygote process and simplified the kernel, reducing the attack surface for malware.
-Android 15–16 (Deep Optimization)
Support: Pure 64-bit environment with hardware-level optimizations.
Focus:
16 KB Page Size: Android 15 introduced support for 16 KB memory pages (up from 4 KB). This allows the CPU to manage memory more efficiently, resulting in a 5–10% performance boost for memory-intensive apps.
Modular ART: The Android Runtime (ART) is now updated via Google Play, meaning performance improvements reach devices instantly without waiting for a full OS update.

Why 64-bit Apps are Faster on Android 16 vs. Android 9
While both versions can run 64-bit code, a 64-bit app on Android 16 outperforms its counterpart on Android 9 due to several key factors:
-Memory Management (16 KB Pages): Android 16-optimized apps handle large datasets much faster. The CPU does less "bookkeeping" when moving data from RAM to cache, which was a bottleneck in the Android 9 era.
Instruction Set Advances (ARMv9): Modern chips running Android 16 use the ARMv9 architecture. It includes features like SVE2 (Scalable Vector Extension), which speeds up AI, imaging, and encryption—features that simply didn't exist in the Android 9/ARMv8 days.
-Elimination of "Dual-Stack" Overhead: Android 9 is always "listening" for 32-bit instructions. Android 16 focuses 100% of CPU cache and execution resources on 64-bit pathways, leading to better branch prediction and less wasted clock cycles.
Evolved ART Compiler: The Android Runtime (ART) in version 16 uses advanced profile-guided optimization (PGO). It learns how you use an app and re-compiles the most-used parts into highly efficient machine code, a process far more primitive in Android 9.
Reduced Kernel Contention: By dropping 32-bit support, the OS kernel is leaner. This reduces the time the CPU spends switching between "user mode" and "kernel mode," making app interactions feel snappier.