144 lines
4.1 KiB
Markdown
144 lines
4.1 KiB
Markdown
# Phase 4 Perf Profiling - Files Index
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**Date**: 2025-12-14
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**Status**: Complete
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## Created Documents
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### 1. Primary Analysis
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**File**: `/mnt/workdisk/public_share/hakmem/docs/analysis/PHASE4_PERF_PROFILE_ANALYSIS.md`
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**Size**: ~5000 words
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**Contents**:
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- Detailed perf report breakdown
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- Candidate analysis (tiny_alloc_gate_fast, free_tiny_fast_cold, ENV gates)
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- Shape optimization plateau analysis
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- E1 implementation plan (ENV snapshot consolidation)
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- Alternative targets (E2/E3/E4)
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### 2. Executive Summary
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**File**: `/mnt/workdisk/public_share/hakmem/docs/analysis/PHASE4_PERF_PROFILE_FINAL_REPORT.md`
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**Size**: ~3000 words
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**Contents**:
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- Executive summary
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- Top hotspots analysis
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- Selected target (E1 ENV Snapshot Consolidation)
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- Implementation roadmap
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- Success criteria checklist
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### 3. Files Index (This Document)
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**File**: `/mnt/workdisk/public_share/hakmem/docs/analysis/PHASE4_PROFILING_FILES_INDEX.md`
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**Contents**:
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- List of all created/modified files
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- Quick reference guide
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## Modified Documents
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### 1. CURRENT_TASK.md
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**File**: `/mnt/workdisk/public_share/hakmem/CURRENT_TASK.md`
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**Changes**:
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- Added Phase 4 perf profiling summary (lines 3-39)
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- Key findings: ENV gate overhead (3.26%), shape plateau analysis
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- Next target: Phase 4 E1 - ENV Snapshot Consolidation
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## Perf Data Artifacts
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### 1. Raw Perf Data
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**File**: `/mnt/workdisk/public_share/hakmem/perf.data`
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**Format**: Binary (perf record output)
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**Size**: 0.059 MB
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**Samples**: 922 @ 999Hz
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**Command**:
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```bash
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HAKMEM_PROFILE=MIXED_TINYV3_C7_SAFE \
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perf record -F 999 -- ./bench_random_mixed_hakmem 40000000 400 1
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```
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### 2. Perf Report (Full)
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**File**: `/tmp/perf_report_full.txt`
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**Format**: Text (perf report --stdio output)
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**Contents**: Full symbol-sorted report with self% breakdown
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### 3. Perf Summary
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**File**: `/tmp/perf_summary.txt`
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**Format**: Text (quick reference)
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**Contents**: Top hotspots, selected target, perf command reference
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## Key Findings
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### ENV Gate Overhead (3.26% Combined)
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1. `tiny_c7_ultra_enabled_env()`: 1.28%
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2. `tiny_front_v3_enabled()`: 1.01%
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3. `tiny_metadata_cache_enabled()`: 0.97%
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**Root Cause**: 3 separate TLS reads + lazy init checks on every hot path call
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### Shape Optimization Plateau
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- B3 (Routing Shape): +2.89% (first pass)
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- D3 (Alloc Gate Shape): +0.56% NEUTRAL (diminishing returns)
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- **Lesson**: Branch prediction saturated, next frontier is caching/structural changes
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### Selected Next Target
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**Phase 4 E1**: ENV Snapshot Consolidation
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- Expected gain: +3.0-3.5%
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- Approach: Consolidate all ENV gates into single TLS snapshot struct
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- Precedent: `tiny_front_v3_snapshot` (proven pattern)
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## Quick Navigation
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### Detailed Analysis
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```bash
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cat /mnt/workdisk/public_share/hakmem/docs/analysis/PHASE4_PERF_PROFILE_ANALYSIS.md
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```
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### Executive Summary
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```bash
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cat /mnt/workdisk/public_share/hakmem/docs/analysis/PHASE4_PERF_PROFILE_FINAL_REPORT.md
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```
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### Current Task Status
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```bash
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head -100 /mnt/workdisk/public_share/hakmem/CURRENT_TASK.md
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```
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### Perf Commands (Re-run)
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```bash
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# Profile
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HAKMEM_PROFILE=MIXED_TINYV3_C7_SAFE \
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perf record -F 999 -- ./bench_random_mixed_hakmem 40000000 400 1
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# Report (top 80)
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perf report --stdio --no-children --sort=symbol | head -80
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# Annotate specific function
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perf annotate --stdio tiny_alloc_gate_fast.lto_priv.0 | head -100
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```
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## Next Steps
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1. **Phase 4 E1 Implementation** (2-3 days):
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- Create `core/box/hakmem_env_snapshot_box.h/c`
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- Migrate priority ENV gates (C7 ultra, front_v3, metadata_cache)
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- Refactor ~14 call sites
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- A/B test (Mixed 10-run, target +2.5%)
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- Health check, promote to default if GO
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2. **Phase 4 E2** (SECONDARY, defer until E1 complete):
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- Per-class alloc fast path specialization
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- Expected gain: +2-3%
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3. **Phase 4 E3** (TERTIARY, extends E1):
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- Free path ENV gate consolidation
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- Expected gain: +0.4-0.6%
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## References
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- **Baseline**: 46.37M ops/s (MIXED_TINYV3_C7_SAFE, Phase 3 + D1)
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- **Target**: 47.8M ops/s (+3.0% via E1)
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- **Profile**: MIXED_TINYV3_C7_SAFE (20M iterations, ws=400)
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- **Workload**: bench_random_mixed_hakmem (50% alloc / 50% free)
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---
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**Status**: COMPLETE - Ready for Phase 4 E1
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**Date**: 2025-12-14
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