Phase 67a: Layout tax forensics foundation (SSOT + measurement box)
Changes:
- scripts/box/layout_tax_forensics_box.sh: New measurement harness
* Baseline vs treatment 10-run throughput comparison
* Automated perf stat collection (cycles, IPC, branches, misses, TLB)
* Binary metadata (size, section info)
* Output to results/layout_tax_forensics/
- docs/analysis/PHASE67A_LAYOUT_TAX_FORENSICS_SSOT.md: Diagnostic reference
* Decision tree: GO/NEUTRAL/NO-GO classification
* Symptom→root-cause mapping (IPC/branch-miss/dTLB/cache-miss)
* Phase 64 case study analysis (IPC 2.05→1.98)
* Operational guidelines for Phase 67b+ optimizations
- CURRENT_TASK.md: Phase 67a marked complete, operational
Outcome:
- Layout tax diagnosis now reproducible in single measurement pass
- Enables fast GO/NO-GO decision for future code removal/reordering attempts
- Foundation for M2 (55% target) structural exploration without regression risk
🤖 Generated with Claude Code
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>
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