129 lines
3.8 KiB
Markdown
129 lines
3.8 KiB
Markdown
# Phase 87: Inline Slots Overflow Observation - Infrastructure Setup (COMPLETE)
|
|
|
|
## Phase 87-1: Telemetry Box Created ✓
|
|
|
|
### Files Added
|
|
|
|
1. **core/box/tiny_inline_slots_overflow_stats_box.h**
|
|
- Global counter structure: `TinyInlineSlotsOverflowStats`
|
|
- Counters: C3/C4/C5/C6 push_full, pop_empty, overflow_to_uc, overflow_to_legacy
|
|
- Fast-path inline API with `__builtin_expect()` for zero-cost when disabled
|
|
- Enabled via compile-time gate:
|
|
- `HAKMEM_INLINE_SLOTS_OVERFLOW_STATS_COMPILED=0/1` (default 0)
|
|
- Non-RELEASE builds can also enable it (depending on build flags)
|
|
|
|
2. **core/box/tiny_inline_slots_overflow_stats_box.c**
|
|
- Global state initialization
|
|
- Refresh function placeholder
|
|
- Report function for final statistics output
|
|
|
|
### Makefile Integration
|
|
|
|
- Added `core/box/tiny_inline_slots_overflow_stats_box.o` to:
|
|
- OBJS_BASE
|
|
- BENCH_HAKMEM_OBJS_BASE
|
|
- TINY_BENCH_OBJS_BASE
|
|
- OBSERVE build enables telemetry explicitly:
|
|
- `make bench_random_mixed_hakmem_observe` adds `-DHAKMEM_INLINE_SLOTS_OVERFLOW_STATS_COMPILED=1`
|
|
|
|
### Build Status
|
|
|
|
✓ Successfully compiled (no errors, no warnings in new code)
|
|
✓ Binary ready: `bench_random_mixed_hakmem`
|
|
|
|
---
|
|
|
|
## Next: Phase 87-2 - Counter Integration Points
|
|
|
|
To enable overflow measurement, counters must be injected at:
|
|
|
|
### Free Path (Push FULL)
|
|
- Location: `core/front/tiny_c6_inline_slots.h:37` (c6_inline_push)
|
|
- Trigger: When ring is FULL, return 0
|
|
- Counter: `tiny_inline_slots_count_push_full(6)`
|
|
|
|
- Similar for C3 (`core/front/tiny_c3_inline_slots.h`), C4, C5
|
|
|
|
### Alloc Path (Pop EMPTY)
|
|
- Location: `core/front/tiny_c6_inline_slots.h:54` (c6_inline_pop)
|
|
- Trigger: When ring is EMPTY, return NULL
|
|
- Counter: `tiny_inline_slots_count_pop_empty(6)`
|
|
|
|
- Similar for C3, C4, C5
|
|
|
|
### Fallback Destinations (Unified Cache)
|
|
- Location: `core/front/tiny_unified_cache.h:177-216` (unified_cache_push)
|
|
- Trigger: When unified cache is FULL, return 0
|
|
- Counter: `tiny_inline_slots_count_overflow_to_uc()`
|
|
|
|
- Also: when unified_cache_push returns 0, legacy path gets called
|
|
- Counter: `tiny_inline_slots_count_overflow_to_legacy()`
|
|
|
|
---
|
|
|
|
## Testing Plan (Phase 87-2)
|
|
|
|
### Observation Conditions
|
|
- **Profile**: MIXED_TINYV3_C7_SAFE
|
|
- **Working Set**: WS=400 (default inline slots conditions)
|
|
- **Iterations**: 20M (ITERS=20000000)
|
|
- **Runs**: single-run OBSERVE preflight (SSOT throughput runs remain Standard/FAST)
|
|
|
|
### Expected Output
|
|
Debug build will print statistics:
|
|
```
|
|
=== PHASE 87: INLINE SLOTS OVERFLOW STATS ===
|
|
|
|
PUSH FULL (Free Path Ring Overflow):
|
|
C3: ...
|
|
C4: ...
|
|
C5: ...
|
|
C6: ...
|
|
|
|
POP EMPTY (Alloc Path Ring Underflow):
|
|
C3: ...
|
|
C4: ...
|
|
C5: ...
|
|
C6: ...
|
|
|
|
Note: `OVERFLOW DESTINATIONS` counters are optional and may remain 0 unless explicitly instrumented at fallback call sites.
|
|
```
|
|
|
|
### GO/NO-GO Decision Logic
|
|
|
|
**GO for Phase 88** if:
|
|
- `(push_full + pop_empty) / (20M * 3 runs) ≥ 0.1%`
|
|
- Indicates sufficient overflow frequency to warrant batch optimization
|
|
|
|
**NO-GO for Phase 88** if:
|
|
- Overflow rate < 0.1%
|
|
- Suggests overhead reduction ROI is minimal
|
|
- Consider alternative optimization layers
|
|
|
|
---
|
|
|
|
## Architecture Notes
|
|
|
|
- Counters use `_Atomic` for thread-safety (single increment per operation)
|
|
- Zero overhead in RELEASE builds (compile-time constant folding)
|
|
- Reporting happens on exit (calls `tiny_inline_slots_overflow_report_stats()`)
|
|
- Call point: Should add to bench program exit sequence
|
|
|
|
---
|
|
|
|
## Files Status
|
|
|
|
| File | Status |
|
|
|------|--------|
|
|
| tiny_inline_slots_overflow_stats_box.h | ✓ Created |
|
|
| tiny_inline_slots_overflow_stats_box.c | ✓ Created |
|
|
| Makefile | ✓ Updated (object files added) |
|
|
| C3/C4/C5/C6 inline slots | ⏳ Pending counter integration |
|
|
| Observation binary build | ⏳ Pending debug build |
|
|
|
|
---
|
|
|
|
## Ready for Phase 87-2
|
|
|
|
Next action: Inject counters into inline slots and run RUNS=3 observation.
|