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hakmem/core/box/pagefault_telemetry_box.d

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Phase 23 Unified Cache + PageFaultTelemetry generalization: Mid/VM page-fault bottleneck identified Summary: - Phase 23 Unified Cache: +30% improvement (Random Mixed 256B: 18.18M → 23.68M ops/s) - PageFaultTelemetry: Extended to generic buckets (C0-C7, MID, L25, SSM) - Measurement-driven decision: Mid/VM page-faults (80-100K) >> Tiny (6K) → prioritize Mid/VM optimization Phase 23 Changes: 1. Unified Cache implementation (core/front/tiny_unified_cache.{c,h}) - Direct SuperSlab carve (TLS SLL bypass) - Self-contained pop-or-refill pattern - ENV: HAKMEM_TINY_UNIFIED_CACHE=1, HAKMEM_TINY_UNIFIED_C{0-7}=128 2. Fast path pruning (tiny_alloc_fast.inc.h, tiny_free_fast_v2.inc.h) - Unified ON → direct cache access (skip all intermediate layers) - Alloc: unified_cache_pop_or_refill() → immediate fail to slow - Free: unified_cache_push() → fallback to SLL only if full PageFaultTelemetry Changes: 3. Generic bucket architecture (core/box/pagefault_telemetry_box.{c,h}) - PF_BUCKET_{C0-C7, MID, L25, SSM} for domain-specific measurement - Integration: hak_pool_try_alloc(), l25_alloc_new_run(), shared_pool_allocate_superslab_unlocked() 4. Measurement results (Random Mixed 500K / 256B): - Tiny C2-C7: 2-33 pages, high reuse (64-3.8 touches/page) - SSM: 512 pages (initialization footprint) - MID/L25: 0 (unused in this workload) - Mid/Large VM benchmarks: 80-100K page-faults (13-16x higher than Tiny) Ring Cache Enhancements: 5. Hot Ring Cache (core/front/tiny_ring_cache.{c,h}) - ENV: HAKMEM_TINY_HOT_RING_ENABLE=1, HAKMEM_TINY_HOT_RING_C{0-7}=size - Conditional compilation cleanup Documentation: 6. Analysis reports - RANDOM_MIXED_BOTTLENECK_ANALYSIS.md: Page-fault breakdown - RANDOM_MIXED_SUMMARY.md: Phase 23 summary - RING_CACHE_ACTIVATION_GUIDE.md: Ring cache usage - CURRENT_TASK.md: Updated with Phase 23 results and Phase 24 plan Next Steps (Phase 24): - Target: Mid/VM PageArena/HotSpanBox (page-fault reduction 80-100K → 30-40K) - Tiny SSM optimization deferred (low ROI, ~6K page-faults already optimal) - Expected improvement: +30-50% for Mid/Large workloads Generated with Claude Code Co-Authored-By: Claude <noreply@anthropic.com>
2025-11-17 02:47:58 +09:00
core/box/pagefault_telemetry_box.o: core/box/pagefault_telemetry_box.c \
P0 Optimization: Shared Pool fast path with O(1) metadata lookup Performance Results: - Throughput: 2.66M ops/s → 3.8M ops/s (+43% improvement) - sp_meta_find_or_create: O(N) linear scan → O(1) direct pointer - Stage 2 metadata scan: 100% → 10-20% (80-90% reduction via hints) Core Optimizations: 1. O(1) Metadata Lookup (superslab_types.h) - Added `shared_meta` pointer field to SuperSlab struct - Eliminates O(N) linear search through ss_metadata[] array - First access: O(N) scan + cache | Subsequent: O(1) direct return 2. sp_meta_find_or_create Fast Path (hakmem_shared_pool.c) - Check cached ss->shared_meta first before linear scan - Cache pointer after successful linear scan for future lookups - Reduces 7.8% CPU hotspot to near-zero for hot paths 3. Stage 2 Class Hints Fast Path (hakmem_shared_pool_acquire.c) - Try class_hints[class_idx] FIRST before full metadata scan - Uses O(1) ss->shared_meta lookup for hint validation - __builtin_expect() for branch prediction optimization - 80-90% of acquire calls now skip full metadata scan 4. Proper Initialization (ss_allocation_box.c) - Initialize shared_meta = NULL in superslab_allocate() - Ensures correct NULL-check semantics for new SuperSlabs Additional Improvements: - Updated ptr_trace and debug ring for release build efficiency - Enhanced ENV variable documentation and analysis - Added learner_env_box.h for configuration management - Various Box optimizations for reduced overhead Thread Safety: - All atomic operations use correct memory ordering - shared_meta cached under mutex protection - Lock-free Stage 2 uses proper CAS with acquire/release semantics Testing: - Benchmark: 1M iterations, 3.8M ops/s stable - Build: Clean compile RELEASE=0 and RELEASE=1 - No crashes, memory leaks, or correctness issues Next Optimization Candidates: - P1: Per-SuperSlab free slot bitmap for O(1) slot claiming - P2: Reduce Stage 2 critical section size - P3: Page pre-faulting (MAP_POPULATE) 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
2025-12-04 16:21:54 +09:00
core/box/pagefault_telemetry_box.h core/box/../hakmem_tiny_stats_api.h \
core/box/../hakmem_stats_master.h
Phase 23 Unified Cache + PageFaultTelemetry generalization: Mid/VM page-fault bottleneck identified Summary: - Phase 23 Unified Cache: +30% improvement (Random Mixed 256B: 18.18M → 23.68M ops/s) - PageFaultTelemetry: Extended to generic buckets (C0-C7, MID, L25, SSM) - Measurement-driven decision: Mid/VM page-faults (80-100K) >> Tiny (6K) → prioritize Mid/VM optimization Phase 23 Changes: 1. Unified Cache implementation (core/front/tiny_unified_cache.{c,h}) - Direct SuperSlab carve (TLS SLL bypass) - Self-contained pop-or-refill pattern - ENV: HAKMEM_TINY_UNIFIED_CACHE=1, HAKMEM_TINY_UNIFIED_C{0-7}=128 2. Fast path pruning (tiny_alloc_fast.inc.h, tiny_free_fast_v2.inc.h) - Unified ON → direct cache access (skip all intermediate layers) - Alloc: unified_cache_pop_or_refill() → immediate fail to slow - Free: unified_cache_push() → fallback to SLL only if full PageFaultTelemetry Changes: 3. Generic bucket architecture (core/box/pagefault_telemetry_box.{c,h}) - PF_BUCKET_{C0-C7, MID, L25, SSM} for domain-specific measurement - Integration: hak_pool_try_alloc(), l25_alloc_new_run(), shared_pool_allocate_superslab_unlocked() 4. Measurement results (Random Mixed 500K / 256B): - Tiny C2-C7: 2-33 pages, high reuse (64-3.8 touches/page) - SSM: 512 pages (initialization footprint) - MID/L25: 0 (unused in this workload) - Mid/Large VM benchmarks: 80-100K page-faults (13-16x higher than Tiny) Ring Cache Enhancements: 5. Hot Ring Cache (core/front/tiny_ring_cache.{c,h}) - ENV: HAKMEM_TINY_HOT_RING_ENABLE=1, HAKMEM_TINY_HOT_RING_C{0-7}=size - Conditional compilation cleanup Documentation: 6. Analysis reports - RANDOM_MIXED_BOTTLENECK_ANALYSIS.md: Page-fault breakdown - RANDOM_MIXED_SUMMARY.md: Phase 23 summary - RING_CACHE_ACTIVATION_GUIDE.md: Ring cache usage - CURRENT_TASK.md: Updated with Phase 23 results and Phase 24 plan Next Steps (Phase 24): - Target: Mid/VM PageArena/HotSpanBox (page-fault reduction 80-100K → 30-40K) - Tiny SSM optimization deferred (low ROI, ~6K page-faults already optimal) - Expected improvement: +30-50% for Mid/Large workloads Generated with Claude Code Co-Authored-By: Claude <noreply@anthropic.com>
2025-11-17 02:47:58 +09:00
core/box/pagefault_telemetry_box.h:
core/box/../hakmem_tiny_stats_api.h:
P0 Optimization: Shared Pool fast path with O(1) metadata lookup Performance Results: - Throughput: 2.66M ops/s → 3.8M ops/s (+43% improvement) - sp_meta_find_or_create: O(N) linear scan → O(1) direct pointer - Stage 2 metadata scan: 100% → 10-20% (80-90% reduction via hints) Core Optimizations: 1. O(1) Metadata Lookup (superslab_types.h) - Added `shared_meta` pointer field to SuperSlab struct - Eliminates O(N) linear search through ss_metadata[] array - First access: O(N) scan + cache | Subsequent: O(1) direct return 2. sp_meta_find_or_create Fast Path (hakmem_shared_pool.c) - Check cached ss->shared_meta first before linear scan - Cache pointer after successful linear scan for future lookups - Reduces 7.8% CPU hotspot to near-zero for hot paths 3. Stage 2 Class Hints Fast Path (hakmem_shared_pool_acquire.c) - Try class_hints[class_idx] FIRST before full metadata scan - Uses O(1) ss->shared_meta lookup for hint validation - __builtin_expect() for branch prediction optimization - 80-90% of acquire calls now skip full metadata scan 4. Proper Initialization (ss_allocation_box.c) - Initialize shared_meta = NULL in superslab_allocate() - Ensures correct NULL-check semantics for new SuperSlabs Additional Improvements: - Updated ptr_trace and debug ring for release build efficiency - Enhanced ENV variable documentation and analysis - Added learner_env_box.h for configuration management - Various Box optimizations for reduced overhead Thread Safety: - All atomic operations use correct memory ordering - shared_meta cached under mutex protection - Lock-free Stage 2 uses proper CAS with acquire/release semantics Testing: - Benchmark: 1M iterations, 3.8M ops/s stable - Build: Clean compile RELEASE=0 and RELEASE=1 - No crashes, memory leaks, or correctness issues Next Optimization Candidates: - P1: Per-SuperSlab free slot bitmap for O(1) slot claiming - P2: Reduce Stage 2 critical section size - P3: Page pre-faulting (MAP_POPULATE) 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>
2025-12-04 16:21:54 +09:00
core/box/../hakmem_stats_master.h:
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