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OPPO Kernel Craftsman
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OPPO Kernel Craftsman

Sharing Linux kernel-related cutting-edge technology, technical articles, technical news, and curated tutorials

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Recent Articles

Latest from OPPO Kernel Craftsman

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OPPO Kernel Craftsman
OPPO Kernel Craftsman
May 26, 2023 · Fundamentals

Understanding Linux rwsem Read‑Write Semaphore in Kernel 5.15.81

Linux introduced the read‑write semaphore (rwsem) as a sleep lock that lets multiple readers hold the lock concurrently, improving read‑heavy workload performance, and the article details its internal state representation, acquisition paths for reads and writes, optimistic spinning, handoff mechanisms, and trade‑offs, noting that mobile kernels may need further tuning.

Linux kernelconcurrencyoptimistic spin
0 likes · 22 min read
Understanding Linux rwsem Read‑Write Semaphore in Kernel 5.15.81
OPPO Kernel Craftsman
OPPO Kernel Craftsman
May 12, 2023 · Mobile Development

eBPF Technology and Its Application on Android Platform

The article explains Android’s emerging eBPF support, detailing how to write, compile, load, attach, and debug BPF programs—including map handling, permission controls, perf‑event reporting, and practical debugging steps—while highlighting its current preliminary status and vast potential for kernel‑level monitoring on mobile devices.

AndroidBPF mapsKernel Extension
0 likes · 9 min read
eBPF Technology and Its Application on Android Platform
OPPO Kernel Craftsman
OPPO Kernel Craftsman
Apr 28, 2023 · Fundamentals

Energy Aware Scheduling (EAS) in the Android Kernel: Concepts, Models, and Thread Selection

Energy Aware Scheduling (EAS) in the Android kernel uses the CPU energy model to select the most energy‑efficient CPU for each thread on heterogeneous big.LITTLE processors, considering capacity, OPP, power, and efficiency ratio; it migrates only if the migration saves more than 6% energy and overall CPU utilization stays below 80%, otherwise reverting to traditional load‑balancing.

Android kernelCPU Power ManagementEnergy Model
0 likes · 11 min read
Energy Aware Scheduling (EAS) in the Android Kernel: Concepts, Models, and Thread Selection
OPPO Kernel Craftsman
OPPO Kernel Craftsman
Apr 21, 2023 · Mobile Development

Android Method Tracing: Implementation and Principles

Android method tracing, a Google‑provided Java‑level profiling tool, captures function‑level execution times via sampling or explicit enter/exit hooks, outlines its startup flow and collection categories, and describes recent Android advances such as JIT‑generated hooks and instrument‑based replacement of trace‑odex support.

AndroidAndroid DevelopmentInstrumentation
0 likes · 9 min read
Android Method Tracing: Implementation and Principles
OPPO Kernel Craftsman
OPPO Kernel Craftsman
Apr 14, 2023 · Fundamentals

Pipeline Domain Design in Multimedia Frameworks: Concepts, Comparative Analysis, and Implementation

The article defines pipeline domain design concepts, compares major multimedia frameworks such as FFmpeg, GStreamer, MediaPipe and AVPipeline, and demonstrates a configurable, extensible node‑based architecture that enables fast plugin integration and adaptable audio‑video pipelines across diverse business scenarios and platforms.

AIFrameworkMultimedia
0 likes · 39 min read
Pipeline Domain Design in Multimedia Frameworks: Concepts, Comparative Analysis, and Implementation
OPPO Kernel Craftsman
OPPO Kernel Craftsman
Apr 7, 2023 · Fundamentals

Overview of Bluetooth Technology and Audio Specifications

Bluetooth has progressed from its 1994 origins to a versatile, low‑power platform supporting HFP, A2DP, and the newer BAP audio profiles, mandatory SBC and optional high‑quality codecs such as AAC, apt‑X, LDAC, and the efficient LC3, while LE Audio adds multi‑stream, broadcast capabilities and reduced latency for modern wireless audio experiences.

BLEBluetoothLow Energy
0 likes · 13 min read
Overview of Bluetooth Technology and Audio Specifications
OPPO Kernel Craftsman
OPPO Kernel Craftsman
Mar 17, 2023 · Operations

Understanding Synchronization Mechanisms and RCU in the Linux Kernel

Linux kernel synchronization requires protecting shared mutable state from concurrent access using primitives such as spinlocks, mutexes, read‑write locks, or lock‑less techniques like RCU, which copies data and waits for a grace period, each offering distinct performance, latency, and complexity trade‑offs.

Linux kernelRCUSpinlock
0 likes · 26 min read
Understanding Synchronization Mechanisms and RCU in the Linux Kernel
OPPO Kernel Craftsman
OPPO Kernel Craftsman
Mar 10, 2023 · Fundamentals

CMA (Contiguous Memory Allocator) Technical Principle Analysis and Source Code Interpretation

Linux’s Contiguous Memory Allocator (CMA) reserves and manages large physical memory blocks for devices by integrating with the Buddy system, using structures like struct cma, bitmap allocation, and APIs such as cma_init_reserved_mem and cma_alloc, while handling page migration, LRU and per‑CPU PCP caches to ensure efficient allocation and release.

Buddy systemCMAContiguous Memory
0 likes · 15 min read
CMA (Contiguous Memory Allocator) Technical Principle Analysis and Source Code Interpretation
OPPO Kernel Craftsman
OPPO Kernel Craftsman
Mar 3, 2023 · Mobile Development

Understanding Java Object Locks and Their Implementation in the Android Runtime (ART)

The article explains how Java’s synchronized keyword works by describing instance, static and block locks, the monitor‑enter/exit bytecodes, the ART object header’s lock word states (thin, fat, hash, forwarding), lock inflation mechanisms, and the internal runtime functions that implement Object.wait(), notify() and related futex handling.

Android RuntimeJVMJava
0 likes · 13 min read
Understanding Java Object Locks and Their Implementation in the Android Runtime (ART)