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c19bb6a3bc
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Phase 6-B: Header-based Mid MT free (lock-free, +2.65% improvement)
Performance Results (bench_mid_mt_gap, 1KB-8KB, ws=256):
- Before: 41.0 M ops/s (mutex-protected registry)
- After: 42.09 M ops/s (+2.65% improvement)
Expected vs Actual:
- Expected: +17-27% (based on perf showing 13.98% mutex overhead)
- Actual: +2.65% (needs investigation)
Implementation:
- Added MidMTHeader (8 bytes) to each Mid MT allocation
- Allocation: Write header with block_size, class_idx, magic (0xAB42)
- Free: Read header for O(1) metadata lookup (no mutex!)
- Eliminated entire registry infrastructure (127 lines deleted)
Changes:
- core/hakmem_mid_mt.h: Added MidMTHeader, removed registry structures
- core/hakmem_mid_mt.c: Updated alloc/free, removed registry functions
- core/box/mid_free_route_box.h: Header-based detection instead of registry lookup
Code Quality:
✅ Lock-free (no pthread_mutex operations)
✅ Simpler (O(1) header read vs O(log N) binary search)
✅ Smaller binary (127 lines deleted)
✅ Positive improvement (no regression)
Next: Investigate why improvement is smaller than expected
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
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2025-11-29 15:45:29 +09:00 |
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3daf75e57f
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Phase 5-Step2: Mid Free Route Box (+28.9x free perf, 1.53x faster than system)
Fix critical 19x free() slowdown in Mid MT allocator (1KB-8KB range).
Root Cause:
- Mid MT registers chunks in MidGlobalRegistry
- Free path searches Pool's mid_desc registry (different registry!)
- Result: 100% lookup failure → 4x cascading lookups → libc fallback
Solution (Box Pattern):
- Created core/box/mid_free_route_box.h
- Try Mid MT registry BEFORE classify_ptr() in free()
- Direct route to mid_mt_free() if found
- Fall through to existing path if not found
Performance Results (bench_mid_mt_gap, 1KB-8KB allocs):
- Before: 1.49 M ops/s (19x slower than system malloc)
- After: 41.0 M ops/s (+28.9x improvement)
- vs System malloc: 1.53x faster (41.0 vs 26.8 M ops/s)
Files:
- core/box/mid_free_route_box.h (NEW) - Mid Free Route Box
- core/box/hak_wrappers.inc.h - Add mid_free_route_try() call
- core/hakmem_mid_mt.h - Fix mid_get_min_size() (1024 not 2048)
- bench_mid_mt_gap.c (NEW) - Targeted 1KB-8KB benchmark
- Makefile - Add bench_mid_mt_gap targets
Box Pattern: ✅ Single responsibility, clear contract, testable, minimal change
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
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2025-11-29 14:18:20 +09:00 |
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