|
|
1755257f60
|
Comprehensive Profiling Analysis: Phase 1 Complete with Major Discoveries
## Key Findings:
1. Prefault Box defaults to OFF (intentional, due to 4MB MAP_POPULATE bug fix)
2. User-space HAKMEM code is NOT the bottleneck (<1% CPU time)
3. TLB misses (48.65%) are NOT from SuperSlab allocations - mostly from TLS/libc
4. THP and PREFAULT optimizations have ZERO impact on dTLB misses
5. Page zeroing (11.65%) is the REAL bottleneck, not memory allocation
## Session Deliverables:
- COMPREHENSIVE_PROFILING_ANALYSIS_20251204.md: Initial analysis
- PROFILING_INSIGHTS_AND_RECOMMENDATIONS_20251204.md: Task investigation
- PHASE1_TEST_RESULTS_MAJOR_DISCOVERY_20251204.md: Phase 1 test results
- SESSION_SUMMARY_FINDINGS_20251204.md: Final summary
## Phase 2 Recommendations:
1. Investigate lazy zeroing (11.65% of cycles)
2. Analyze page fault sources (debug with callgraph)
3. Skip THP/PREFAULT/Hugepage optimization (proven ineffective)
## Paradigm Shift:
Old: THP/PREFAULT → 2-3x speedup
New: Lazy zeroing → 1.10x-1.15x speedup (realistic)
🐱 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
|
2025-12-04 20:41:53 +09:00 |
|
