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hakmem/hakmem_smallmid.d

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Phase 17-1: Small-Mid Allocator - TLS Frontend Cache (結果: ±0.3%, 層分離成功) Summary: ======== Phase 17-1 implements Small-Mid allocator as TLS frontend cache with Tiny backend delegation. Result: Clean layer separation achieved with minimal overhead (±0.3%), but no performance gain. Conclusion: Frontend-only approach is dead end. Phase 17-2 (dedicated backend) required for 2-3x target. Implementation: =============== 1. Small-Mid TLS frontend (256B/512B/1KB - 3 classes) - TLS freelist (32/24/16 capacity) - Backend delegation to Tiny C5/C6/C7 - Header conversion (0xa0 → 0xb0) 2. Auto-adjust Tiny boundary - When Small-Mid ON: Tiny auto-limits to C0-C5 (0-255B) - When Small-Mid OFF: Tiny default C0-C7 (0-1023B) - Prevents routing conflict 3. Routing order fix - Small-Mid BEFORE Tiny (critical for proper execution) - Fall-through on TLS miss Files Modified: =============== - core/hakmem_smallmid.h/c: TLS freelist + backend delegation - core/hakmem_tiny.c: tiny_get_max_size() auto-adjust - core/box/hak_alloc_api.inc.h: Routing order (Small-Mid → Tiny) - CURRENT_TASK.md: Phase 17-1 results + Phase 17-2 plan A/B Benchmark Results: ====================== | Size | Config A (OFF) | Config B (ON) | Delta | % Change | |--------|----------------|---------------|----------|----------| | 256B | 5.87M ops/s | 6.06M ops/s | +191K | +3.3% | | 512B | 6.02M ops/s | 5.91M ops/s | -112K | -1.9% | | 1024B | 5.58M ops/s | 5.54M ops/s | -35K | -0.6% | | Overall| 5.82M ops/s | 5.84M ops/s | +20K | +0.3% | Analysis: ========= ✅ SUCCESS: Clean layer separation (Small-Mid ↔ Tiny coexist) ✅ SUCCESS: Minimal overhead (±0.3% = measurement noise) ❌ FAIL: No performance gain (target was 2-4x) Root Cause: ----------- - Delegation overhead = TLS savings (net gain ≈ 0 instructions) - Small-Mid TLS alloc: ~3-5 instructions - Tiny backend delegation: ~3-5 instructions - Header conversion: ~2 instructions - No batching: 1:1 delegation to Tiny (no refill amortization) Lessons Learned: ================ - Frontend-only approach ineffective (backend calls not reduced) - Dedicated backend essential for meaningful improvement - Clean separation achieved = solid foundation for Phase 17-2 Next Steps (Phase 17-2): ======================== - Dedicated Small-Mid SuperSlab backend (separate from Tiny) - TLS batch refill (8-16 blocks per refill) - Optimized 0xb0 header fast path (no delegation) - Target: 12-15M ops/s (2.0-2.6x improvement) 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
2025-11-16 02:37:24 +09:00
hakmem_smallmid.o: core/hakmem_smallmid.c core/hakmem_smallmid.h \
Phase 17-2: Small-Mid Dedicated SuperSlab Backend (実験結果: 70% page fault, 性能改善なし) Summary: ======== Phase 17-2 implements dedicated SuperSlab backend for Small-Mid allocator (256B-1KB). Result: No performance improvement (-0.9%), worse than Phase 17-1 (+0.3%). Root cause: 70% page fault (ChatGPT + perf profiling). Conclusion: Small-Mid専用層戦略は失敗。Tiny SuperSlab最適化が必要。 Implementation: =============== 1. Dedicated Small-Mid SuperSlab pool (1MB, 16 slabs/SS) - Separate from Tiny SuperSlab (no competition) - Batch refill (8-16 blocks per TLS refill) - Direct 0xb0 header writes (no Tiny delegation) 2. Backend architecture - SmallMidSuperSlab: 1MB aligned region, fast ptr→SS lookup - SmallMidSlabMeta: per-slab metadata (capacity/used/carved/freelist) - SmallMidSSHead: per-class pool with LRU tracking 3. Batch refill implementation - smallmid_refill_batch(): 8-16 blocks/call (vs 1 in Phase 17-1) - Freelist priority → bump allocation fallback - Auto SuperSlab expansion when exhausted Files Added: ============ - core/hakmem_smallmid_superslab.h: SuperSlab metadata structures - core/hakmem_smallmid_superslab.c: Backend implementation (~450 lines) Files Modified: =============== - core/hakmem_smallmid.c: Removed Tiny delegation, added batch refill - Makefile: Added hakmem_smallmid_superslab.o to build - CURRENT_TASK.md: Phase 17 完了記録 + Phase 18 計画 A/B Benchmark Results: ====================== | Size | Phase 17-1 (ON) | Phase 17-2 (ON) | Delta | vs Baseline | |--------|-----------------|-----------------|----------|-------------| | 256B | 6.06M ops/s | 5.84M ops/s | -3.6% | -4.1% | | 512B | 5.91M ops/s | 5.86M ops/s | -0.8% | +1.2% | | 1024B | 5.54M ops/s | 5.44M ops/s | -1.8% | +0.4% | | Avg | 5.84M ops/s | 5.71M ops/s | -2.2% | -0.9% | Performance Analysis (ChatGPT + perf): ====================================== ✅ Frontend (TLS/batch refill): OK - Only 30% CPU time - Batch refill logic is efficient - Direct 0xb0 header writes work correctly ❌ Backend (SuperSlab allocation): BOTTLENECK - 70% CPU time in asm_exc_page_fault - mmap(1MB) → kernel page allocation → very slow - New SuperSlab allocation per benchmark run - No warm SuperSlab reuse (used counter never decrements) Root Cause: =========== Small-Mid allocates new SuperSlabs frequently: alloc → TLS miss → refill → new SuperSlab → mmap(1MB) → page fault (70%) Tiny reuses warm SuperSlabs: alloc → TLS miss → refill → existing warm SuperSlab → no page fault Key Finding: "70% page fault" reveals SuperSlab layer needs optimization, NOT frontend layer (TLS/batch refill design is correct). Lessons Learned: ================ 1. ❌ Small-Mid専用層戦略は失敗 (Phase 17-1: +0.3%, Phase 17-2: -0.9%) 2. ✅ Frontend実装は成功 (30% CPU, batch refill works) 3. 🔥 70% page fault = SuperSlab allocation bottleneck 4. ✅ Tiny (6.08M ops/s) is already well-optimized, hard to beat 5. ✅ Layer separation doesn't improve performance - backend optimization needed Next Steps (Phase 18): ====================== ChatGPT recommendation: Optimize Tiny SuperSlab (NOT Small-Mid specific layer) Box SS-Reuse (Priority 1): - Implement meta->freelist reuse (currently bump-only) - Detect slab empty → return to shared_pool - Reuse same SuperSlab for longer (reduce page faults) - Target: 70% page fault → 5-10%, 2-4x improvement Box SS-Prewarm (Priority 2): - Pre-allocate SuperSlabs per class (Phase 11: +6.4%) - Concentrate page faults at benchmark start - Benchmark-only optimization Small-Mid Implementation Status: ================================= - ENV=0 by default (zero overhead, branch predictor learns) - Complete separation from Tiny (no interference) - Valuable as experimental record ("why dedicated layer failed") - Can be removed later if needed (not blocking Tiny optimization) 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
2025-11-16 03:21:13 +09:00
core/hakmem_build_flags.h core/hakmem_smallmid_superslab.h \
core/tiny_region_id.h core/tiny_box_geometry.h \
core/hakmem_tiny_superslab_constants.h core/hakmem_tiny_config.h \
core/ptr_track.h
Phase 17-1: Small-Mid Allocator - TLS Frontend Cache (結果: ±0.3%, 層分離成功) Summary: ======== Phase 17-1 implements Small-Mid allocator as TLS frontend cache with Tiny backend delegation. Result: Clean layer separation achieved with minimal overhead (±0.3%), but no performance gain. Conclusion: Frontend-only approach is dead end. Phase 17-2 (dedicated backend) required for 2-3x target. Implementation: =============== 1. Small-Mid TLS frontend (256B/512B/1KB - 3 classes) - TLS freelist (32/24/16 capacity) - Backend delegation to Tiny C5/C6/C7 - Header conversion (0xa0 → 0xb0) 2. Auto-adjust Tiny boundary - When Small-Mid ON: Tiny auto-limits to C0-C5 (0-255B) - When Small-Mid OFF: Tiny default C0-C7 (0-1023B) - Prevents routing conflict 3. Routing order fix - Small-Mid BEFORE Tiny (critical for proper execution) - Fall-through on TLS miss Files Modified: =============== - core/hakmem_smallmid.h/c: TLS freelist + backend delegation - core/hakmem_tiny.c: tiny_get_max_size() auto-adjust - core/box/hak_alloc_api.inc.h: Routing order (Small-Mid → Tiny) - CURRENT_TASK.md: Phase 17-1 results + Phase 17-2 plan A/B Benchmark Results: ====================== | Size | Config A (OFF) | Config B (ON) | Delta | % Change | |--------|----------------|---------------|----------|----------| | 256B | 5.87M ops/s | 6.06M ops/s | +191K | +3.3% | | 512B | 6.02M ops/s | 5.91M ops/s | -112K | -1.9% | | 1024B | 5.58M ops/s | 5.54M ops/s | -35K | -0.6% | | Overall| 5.82M ops/s | 5.84M ops/s | +20K | +0.3% | Analysis: ========= ✅ SUCCESS: Clean layer separation (Small-Mid ↔ Tiny coexist) ✅ SUCCESS: Minimal overhead (±0.3% = measurement noise) ❌ FAIL: No performance gain (target was 2-4x) Root Cause: ----------- - Delegation overhead = TLS savings (net gain ≈ 0 instructions) - Small-Mid TLS alloc: ~3-5 instructions - Tiny backend delegation: ~3-5 instructions - Header conversion: ~2 instructions - No batching: 1:1 delegation to Tiny (no refill amortization) Lessons Learned: ================ - Frontend-only approach ineffective (backend calls not reduced) - Dedicated backend essential for meaningful improvement - Clean separation achieved = solid foundation for Phase 17-2 Next Steps (Phase 17-2): ======================== - Dedicated Small-Mid SuperSlab backend (separate from Tiny) - TLS batch refill (8-16 blocks per refill) - Optimized 0xb0 header fast path (no delegation) - Target: 12-15M ops/s (2.0-2.6x improvement) 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
2025-11-16 02:37:24 +09:00
core/hakmem_smallmid.h:
core/hakmem_build_flags.h:
Phase 17-2: Small-Mid Dedicated SuperSlab Backend (実験結果: 70% page fault, 性能改善なし) Summary: ======== Phase 17-2 implements dedicated SuperSlab backend for Small-Mid allocator (256B-1KB). Result: No performance improvement (-0.9%), worse than Phase 17-1 (+0.3%). Root cause: 70% page fault (ChatGPT + perf profiling). Conclusion: Small-Mid専用層戦略は失敗。Tiny SuperSlab最適化が必要。 Implementation: =============== 1. Dedicated Small-Mid SuperSlab pool (1MB, 16 slabs/SS) - Separate from Tiny SuperSlab (no competition) - Batch refill (8-16 blocks per TLS refill) - Direct 0xb0 header writes (no Tiny delegation) 2. Backend architecture - SmallMidSuperSlab: 1MB aligned region, fast ptr→SS lookup - SmallMidSlabMeta: per-slab metadata (capacity/used/carved/freelist) - SmallMidSSHead: per-class pool with LRU tracking 3. Batch refill implementation - smallmid_refill_batch(): 8-16 blocks/call (vs 1 in Phase 17-1) - Freelist priority → bump allocation fallback - Auto SuperSlab expansion when exhausted Files Added: ============ - core/hakmem_smallmid_superslab.h: SuperSlab metadata structures - core/hakmem_smallmid_superslab.c: Backend implementation (~450 lines) Files Modified: =============== - core/hakmem_smallmid.c: Removed Tiny delegation, added batch refill - Makefile: Added hakmem_smallmid_superslab.o to build - CURRENT_TASK.md: Phase 17 完了記録 + Phase 18 計画 A/B Benchmark Results: ====================== | Size | Phase 17-1 (ON) | Phase 17-2 (ON) | Delta | vs Baseline | |--------|-----------------|-----------------|----------|-------------| | 256B | 6.06M ops/s | 5.84M ops/s | -3.6% | -4.1% | | 512B | 5.91M ops/s | 5.86M ops/s | -0.8% | +1.2% | | 1024B | 5.54M ops/s | 5.44M ops/s | -1.8% | +0.4% | | Avg | 5.84M ops/s | 5.71M ops/s | -2.2% | -0.9% | Performance Analysis (ChatGPT + perf): ====================================== ✅ Frontend (TLS/batch refill): OK - Only 30% CPU time - Batch refill logic is efficient - Direct 0xb0 header writes work correctly ❌ Backend (SuperSlab allocation): BOTTLENECK - 70% CPU time in asm_exc_page_fault - mmap(1MB) → kernel page allocation → very slow - New SuperSlab allocation per benchmark run - No warm SuperSlab reuse (used counter never decrements) Root Cause: =========== Small-Mid allocates new SuperSlabs frequently: alloc → TLS miss → refill → new SuperSlab → mmap(1MB) → page fault (70%) Tiny reuses warm SuperSlabs: alloc → TLS miss → refill → existing warm SuperSlab → no page fault Key Finding: "70% page fault" reveals SuperSlab layer needs optimization, NOT frontend layer (TLS/batch refill design is correct). Lessons Learned: ================ 1. ❌ Small-Mid専用層戦略は失敗 (Phase 17-1: +0.3%, Phase 17-2: -0.9%) 2. ✅ Frontend実装は成功 (30% CPU, batch refill works) 3. 🔥 70% page fault = SuperSlab allocation bottleneck 4. ✅ Tiny (6.08M ops/s) is already well-optimized, hard to beat 5. ✅ Layer separation doesn't improve performance - backend optimization needed Next Steps (Phase 18): ====================== ChatGPT recommendation: Optimize Tiny SuperSlab (NOT Small-Mid specific layer) Box SS-Reuse (Priority 1): - Implement meta->freelist reuse (currently bump-only) - Detect slab empty → return to shared_pool - Reuse same SuperSlab for longer (reduce page faults) - Target: 70% page fault → 5-10%, 2-4x improvement Box SS-Prewarm (Priority 2): - Pre-allocate SuperSlabs per class (Phase 11: +6.4%) - Concentrate page faults at benchmark start - Benchmark-only optimization Small-Mid Implementation Status: ================================= - ENV=0 by default (zero overhead, branch predictor learns) - Complete separation from Tiny (no interference) - Valuable as experimental record ("why dedicated layer failed") - Can be removed later if needed (not blocking Tiny optimization) 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
2025-11-16 03:21:13 +09:00
core/hakmem_smallmid_superslab.h:
Phase 17-1: Small-Mid Allocator - TLS Frontend Cache (結果: ±0.3%, 層分離成功) Summary: ======== Phase 17-1 implements Small-Mid allocator as TLS frontend cache with Tiny backend delegation. Result: Clean layer separation achieved with minimal overhead (±0.3%), but no performance gain. Conclusion: Frontend-only approach is dead end. Phase 17-2 (dedicated backend) required for 2-3x target. Implementation: =============== 1. Small-Mid TLS frontend (256B/512B/1KB - 3 classes) - TLS freelist (32/24/16 capacity) - Backend delegation to Tiny C5/C6/C7 - Header conversion (0xa0 → 0xb0) 2. Auto-adjust Tiny boundary - When Small-Mid ON: Tiny auto-limits to C0-C5 (0-255B) - When Small-Mid OFF: Tiny default C0-C7 (0-1023B) - Prevents routing conflict 3. Routing order fix - Small-Mid BEFORE Tiny (critical for proper execution) - Fall-through on TLS miss Files Modified: =============== - core/hakmem_smallmid.h/c: TLS freelist + backend delegation - core/hakmem_tiny.c: tiny_get_max_size() auto-adjust - core/box/hak_alloc_api.inc.h: Routing order (Small-Mid → Tiny) - CURRENT_TASK.md: Phase 17-1 results + Phase 17-2 plan A/B Benchmark Results: ====================== | Size | Config A (OFF) | Config B (ON) | Delta | % Change | |--------|----------------|---------------|----------|----------| | 256B | 5.87M ops/s | 6.06M ops/s | +191K | +3.3% | | 512B | 6.02M ops/s | 5.91M ops/s | -112K | -1.9% | | 1024B | 5.58M ops/s | 5.54M ops/s | -35K | -0.6% | | Overall| 5.82M ops/s | 5.84M ops/s | +20K | +0.3% | Analysis: ========= ✅ SUCCESS: Clean layer separation (Small-Mid ↔ Tiny coexist) ✅ SUCCESS: Minimal overhead (±0.3% = measurement noise) ❌ FAIL: No performance gain (target was 2-4x) Root Cause: ----------- - Delegation overhead = TLS savings (net gain ≈ 0 instructions) - Small-Mid TLS alloc: ~3-5 instructions - Tiny backend delegation: ~3-5 instructions - Header conversion: ~2 instructions - No batching: 1:1 delegation to Tiny (no refill amortization) Lessons Learned: ================ - Frontend-only approach ineffective (backend calls not reduced) - Dedicated backend essential for meaningful improvement - Clean separation achieved = solid foundation for Phase 17-2 Next Steps (Phase 17-2): ======================== - Dedicated Small-Mid SuperSlab backend (separate from Tiny) - TLS batch refill (8-16 blocks per refill) - Optimized 0xb0 header fast path (no delegation) - Target: 12-15M ops/s (2.0-2.6x improvement) 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
2025-11-16 02:37:24 +09:00
core/tiny_region_id.h:
core/tiny_box_geometry.h:
core/hakmem_tiny_superslab_constants.h:
core/hakmem_tiny_config.h:
core/ptr_track.h:
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