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6859d589ea
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Add Box 3 (Pointer Conversion Layer) and fix POOL_TLS_PHASE1 default
## Major Changes
### 1. Box 3: Pointer Conversion Module (NEW)
- File: core/box/ptr_conversion_box.h
- Purpose: Unified BASE ↔ USER pointer conversion (single source of truth)
- API: PTR_BASE_TO_USER(), PTR_USER_TO_BASE()
- Features: Zero-overhead inline, debug mode, NULL-safe, class 7 headerless support
- Design: Header-only, fully modular, no external dependencies
### 2. POOL_TLS_PHASE1 Default OFF (CRITICAL FIX)
- File: build.sh
- Change: POOL_TLS_PHASE1 now defaults to 0 (was hardcoded to 1)
- Impact: Eliminates pthread_mutex overhead on every free() (was causing 3.3x slowdown)
- Usage: Set POOL_TLS_PHASE1=1 env var to enable if needed
### 3. Pointer Conversion Fixes (PARTIAL)
- Files: core/box/front_gate_box.c, core/tiny_alloc_fast.inc.h, etc.
- Status: Partial implementation using Box 3 API
- Note: Work in progress, some conversions still need review
### 4. Performance Investigation Report (NEW)
- File: HOTPATH_PERFORMANCE_INVESTIGATION.md
- Findings:
- Hotpath works (+24% vs baseline) after POOL_TLS fix
- Still 9.2x slower than system malloc due to:
* Heavy initialization (23.85% of cycles)
* Syscall overhead (2,382 syscalls per 100K ops)
* Workload mismatch (C7 1KB is 49.8%, but only C5 256B has hotpath)
* 9.4x more instructions than system malloc
### 5. Known Issues
- SEGV at 20K-30K iterations (pre-existing bug, not related to pointer conversions)
- Root cause: Likely active counter corruption or TLS-SLL chain issues
- Status: Under investigation
## Performance Results (100K iterations, 256B)
- Baseline (Hotpath OFF): 7.22M ops/s
- Hotpath ON: 8.98M ops/s (+24% improvement ✓)
- System malloc: 82.2M ops/s (still 9.2x faster)
## Next Steps
- P0: Fix 20K-30K SEGV bug (GDB investigation needed)
- P1: Lazy initialization (+20-25% expected)
- P1: C7 (1KB) hotpath (+30-40% expected, biggest win)
- P2: Reduce syscalls (+15-20% expected)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
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2025-11-12 01:01:23 +09:00 |
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c9053a43ac
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Phase 6-2.3~6-2.5: Critical bug fixes + SuperSlab optimization (WIP)
## Phase 6-2.3: Fix 4T Larson crash (active counter bug) ✅
**Problem:** 4T Larson crashed with "free(): invalid pointer", OOM errors
**Root cause:** core/hakmem_tiny_refill_p0.inc.h:103
- P0 batch refill moved freelist blocks to TLS cache
- Active counter NOT incremented → double-decrement on free
- Counter underflows → SuperSlab appears full → OOM → crash
**Fix:** Added ss_active_add(tls->ss, from_freelist);
**Result:** 4T stable at 838K ops/s ✅
## Phase 6-2.4: Fix SEGV in random_mixed/mid_large_mt benchmarks ✅
**Problem:** bench_random_mixed_hakmem, bench_mid_large_mt_hakmem → immediate SEGV
**Root cause #1:** core/box/hak_free_api.inc.h:92-95
- "Guess loop" dereferenced unmapped memory when registry lookup failed
**Root cause #2:** core/box/hak_free_api.inc.h:115
- Header magic check dereferenced unmapped memory
**Fix:**
1. Removed dangerous guess loop (lines 92-95)
2. Added hak_is_memory_readable() check before dereferencing header
(core/hakmem_internal.h:277-294 - uses mincore() syscall)
**Result:**
- random_mixed (2KB): SEGV → 2.22M ops/s ✅
- random_mixed (4KB): SEGV → 2.58M ops/s ✅
- Larson 4T: no regression (838K ops/s) ✅
## Phase 6-2.5: Performance investigation + SuperSlab fix (WIP) ⚠️
**Problem:** Severe performance gaps (19-26x slower than system malloc)
**Investigation:** Task agent identified root cause
- hak_is_memory_readable() syscall overhead (100-300 cycles per free)
- ALL frees hit unmapped_header_fallback path
- SuperSlab lookup NEVER called
- Why? g_use_superslab = 0 (disabled by diet mode)
**Root cause:** core/hakmem_tiny_init.inc:104-105
- Diet mode (default ON) disables SuperSlab
- SuperSlab defaults to 1 (hakmem_config.c:334)
- BUT diet mode overrides it to 0 during init
**Fix:** Separate SuperSlab from diet mode
- SuperSlab: Performance-critical (fast alloc/free)
- Diet mode: Memory efficiency (magazine capacity limits only)
- Both are independent features, should not interfere
**Status:** ⚠️ INCOMPLETE - New SEGV discovered after fix
- SuperSlab lookup now works (confirmed via debug output)
- But benchmark crashes (Exit 139) after ~20 lookups
- Needs further investigation
**Files modified:**
- core/hakmem_tiny_init.inc:99-109 - Removed diet mode override
- PERFORMANCE_INVESTIGATION_REPORT.md - Task agent analysis (303x instruction gap)
**Next steps:**
- Investigate new SEGV (likely SuperSlab free path bug)
- OR: Revert Phase 6-2.5 changes if blocking progress
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
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2025-11-07 20:31:01 +09:00 |
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52386401b3
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Debug Counters Implementation - Clean History
Major Features:
- Debug counter infrastructure for Refill Stage tracking
- Free Pipeline counters (ss_local, ss_remote, tls_sll)
- Diagnostic counters for early return analysis
- Unified larson.sh benchmark runner with profiles
- Phase 6-3 regression analysis documentation
Bug Fixes:
- Fix SuperSlab disabled by default (HAKMEM_TINY_USE_SUPERSLAB)
- Fix profile variable naming consistency
- Add .gitignore patterns for large files
Performance:
- Phase 6-3: 4.79 M ops/s (has OOM risk)
- With SuperSlab: 3.13 M ops/s (+19% improvement)
This is a clean repository without large log files.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
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2025-11-05 12:31:14 +09:00 |
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