Mode d’emploi
- Copiez la commande et examinez le paquet avant de l’installer dans votre environnement agent.
- Consultez le document original pour les outils, identifiants et environnements requis.
- Décrivez les entrées et le livrable souhaité ; comparez la sortie aux sources.
npx skills add https://github.com/mohitmishra786/low-level-dev-skills --skill resource-optimization-lowendAvant de commencer
- L’installation n’inclut ni abonnement au modèle, ni quota API, ni accès aux fichiers.
- Étoiles et installations reflètent l’activité, pas un test indépendant de qualité ou de sécurité.
Document Skill original
Rendu depuis le dépôt source en conservant titres, exemples, code, tableaux, liens et images.
Resource Optimization (Low-End Systems)
Purpose
Guide agents through flash and RAM optimization on constrained devices: compiler size flags, linker map analysis, stack usage measurement, dead code elimination, and size-vs-speed tradeoffs — for bare-metal and small RTOS images.
When to Use
- Firmware exceeds flash budget
- Stack overflow in production only
- Choosing
-Osvs-O2on MCU - Finding unexpected
.rodataor.bssgrowth
Workflow
1. Size measurement toolchain
bash
arm-none-eabi-size -A firmware.elf
arm-none-eabi-objdump -h firmware.elf
nm --size-sort -S firmware.elf | tail -202. Linker map file
ld
/* linker.ld */
OUTPUT_FORMAT("elf32-littlearm")
ENTRY(Reset_Handler)
SECTIONS
{
/* ... */
}
/* Generate map */
/* gcc ... -Wl,-Map=firmware.map */bash
grep -E '\.text|\.rodata|\.data|\.bss' firmware.map | headIdentify largest symbols and unexpected library pull-in.
3. Compiler flags
| Flag | Effect |
|---|---|
-Os | Size-first optimization |
-ffunction-sections -fdata-sections | Per-symbol sections |
-Wl,--gc-sections | Drop unused sections |
-flto | Cross-TU dead code elimination |
-specs=nano.specs | Smaller newlib (GCC ARM) |
makefile
CFLAGS += -Os -ffunction-sections -fdata-sections
LDFLAGS += -Wl,--gc-sections -Wl,--print-memory-usage4. Stack analysis
bash
# Static (if built with -fstack-usage)
find . -name '*.su' -exec cat {} \;
# Linker stack symbol
grep _estack firmware.mapRuntime: fill stack with pattern (0xDEADBEEF), run tests, scan high-water mark. FreeRTOS: uxTaskGetStackHighWaterMark.
5. RAM categories
| Section | Tactic |
|---|---|
.bss | Shrink buffers; pool allocators |
.data | Move const to flash (const → .rodata) |
| Heap | Avoid malloc; fixed pools |
| Stack | Reduce nesting; smaller ISR stacks |
6. Size vs speed decision
Hot path in ISR or 1 kHz loop?
├── Yes → -O2 for that file (#pragma GCC optimize)
└── No → -Os globally7. Agent usage
/resource-optimization-lowend Find top 10 flash consumers in firmware.map and suggest -gc-sections fixesCommon Problems
| Symptom | Cause | Fix |
|---|---|---|
| printf pulls 20+ KB | Full newlib printf | _write retarget; tiny printf |
--gc-sections broke IRQ | Section collected | KEEP() in linker script |
| Stack overflow late | Deep call + IRQ nest | Measure HW stack; increase _estack |
| RAM zero but big ELF | .data not loaded | Check VMA/LMA |
| LTO link fail | Mixed compiler versions | Same GCC for all objects |
Related Skills
skills/embedded/linker-scripts— MEMORY/Sections layoutskills/baremetal/baremetal-startup— stack symbolskills/baremetal/low-power-embedded— RAM retentionskills/compilers/gcc— optimization flagsskills/rust/rust-no-std— embedded Rust size patterns
