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83bb8624f6
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Tiny: fix remote sentinel leak → SEGV; add defense-in-depth; PoolTLS: refill-boundary remote drain; build UX help; quickstart docs
Summary
- Fix SEGV root cause in Tiny random_mixed: TINY_REMOTE_SENTINEL leaked from Remote queue into freelist/TLS SLL.
- Clear/guard sentinel at the single boundary where Remote merges to freelist.
- Add minimal defense-in-depth in freelist_pop and TLS SLL pop.
- Silence verbose prints behind debug gates to reduce noise in release runs.
- Pool TLS: integrate Remote Queue drain at refill boundary to avoid unnecessary backend carve/OS calls when possible.
- DX: strengthen build.sh with help/list/verify and add docs/BUILDING_QUICKSTART.md.
Details
- core/superslab/superslab_inline.h: guard head/node against TINY_REMOTE_SENTINEL; sanitize node[0] when splicing local chain; only print diagnostics when debug guard is enabled.
- core/slab_handle.h: freelist_pop breaks on sentinel head (fail-fast under strict).
- core/tiny_alloc_fast_inline.h: TLS SLL pop breaks on sentinel head (rare branch).
- core/tiny_superslab_free.inc.h: sentinel scan log behind debug guard.
- core/pool_refill.c: try pool_remote_pop_chain() before backend carve in pool_refill_and_alloc().
- core/tiny_adaptive_sizing.c: default adaptive logs off; enable via HAKMEM_ADAPTIVE_LOG=1.
- build.sh: add help/list/verify; EXTRA_MAKEFLAGS passthrough; echo pinned flags.
- docs/BUILDING_QUICKSTART.md: add one‑pager for targets/flags/env/perf/strace.
Verification (high level)
- Tiny random_mixed 10k 256/1024: SEGV resolved; runs complete.
- Pool TLS 1T/4T perf: HAKMEM >= system (≈ +0.7% 1T, ≈ +2.9% 4T); syscall counts ~10–13.
Known issues (to address next)
- Tiny random_mixed perf is weak vs system:
- 1T/500k/256: cycles/op ≈ 240 vs ~47 (≈5× slower), IPC ≈0.92, branch‑miss ≈11%.
- 1T/500k/1024: cycles/op ≈ 149 vs ~53 (≈2.8× slower), IPC ≈0.82, branch‑miss ≈10.5%.
- Hypothesis: frequent SuperSlab path for class7 (fast_cap=0), branchy refill/adopt, and hot-path divergence.
- Proposed next steps:
- Introduce fast_cap>0 for class7 (bounded TLS SLL) and a simpler batch refill.
- Add env‑gated Remote Side OFF for 1T A/B (reduce side-table and guards).
- Revisit likely/unlikely and unify adopt boundary sequencing (drain→bind→acquire) for Tiny.
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2025-11-09 16:49:34 +09:00 |
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707056b765
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feat: Phase 7 + Phase 2 - Massive performance & stability improvements
Performance Achievements:
- Tiny allocations: +180-280% (21M → 59-70M ops/s random mixed)
- Single-thread: +24% (2.71M → 3.36M ops/s Larson)
- 4T stability: 0% → 95% (19/20 success rate)
- Overall: 91.3% of System malloc average (target was 40-55%) ✓
Phase 7 (Tasks 1-3): Core Optimizations
- Task 1: Header validation removal (Region-ID direct lookup)
- Task 2: Aggressive inline (TLS cache access optimization)
- Task 3: Pre-warm TLS cache (eliminate cold-start penalty)
Result: +180-280% improvement, 85-146% of System malloc
Critical Bug Fixes:
- Fix 64B allocation crash (size-to-class +1 for header)
- Fix 4T wrapper recursion bugs (BUG #7, #8, #10, #11)
- Remove malloc fallback (30% → 50% stability)
Phase 2a: SuperSlab Dynamic Expansion (CRITICAL)
- Implement mimalloc-style chunk linking
- Unlimited slab expansion (no more OOM at 32 slabs)
- Fix chunk initialization bug (bitmap=0x00000001 after expansion)
Files: core/hakmem_tiny_superslab.c/h, core/superslab/superslab_types.h
Result: 50% → 95% stability (19/20 4T success)
Phase 2b: TLS Cache Adaptive Sizing
- Dynamic capacity: 16-2048 slots based on usage
- High-water mark tracking + exponential growth/shrink
- Expected: +3-10% performance, -30-50% memory
Files: core/tiny_adaptive_sizing.c/h (new)
Phase 2c: BigCache Dynamic Hash Table
- Migrate from fixed 256×8 array to dynamic hash table
- Auto-resize: 256 → 512 → 1024 → 65,536 buckets
- Improved hash function (FNV-1a) + collision chaining
Files: core/hakmem_bigcache.c/h
Expected: +10-20% cache hit rate
Design Flaws Analysis:
- Identified 6 components with fixed-capacity bottlenecks
- SuperSlab (CRITICAL), TLS Cache (HIGH), BigCache/L2.5 (MEDIUM)
- Report: DESIGN_FLAWS_ANALYSIS.md (11 chapters)
Documentation:
- 13 comprehensive reports (PHASE*.md, DESIGN_FLAWS*.md)
- Implementation guides, test results, production readiness
- Bug fix reports, root cause analysis
Build System:
- Makefile: phase7 targets, PREWARM_TLS flag
- Auto dependency generation (-MMD -MP) for .inc files
Known Issues:
- 4T stability: 19/20 (95%) - investigating 1 failure for 100%
- L2.5 Pool dynamic sharding: design only (needs 2-3 days integration)
🤖 Generated with Claude Code (https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
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2025-11-08 17:08:00 +09:00 |
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