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precision-pass

Diagnose PyPTO Pass precision failures using PreCheck/PostCheck verification and pass_compare Op-level comparison.

Updated Sep 15, 2026
Search Tags:#synchronization#operator development#pypto#ascend npu#precision verification#pass debugging#pass_compare
One-click install
npx skills add https://github.com/WangWindow/CANN-BatchMatMulMaxsum --skill precision-pass-wangwindow
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: precision-pass
Source: https://github.com/WangWindow/CANN-BatchMatMulMaxsum/tree/main/.agents/skills/pypto-precision-compare/precision-pass
Command: npx skills add https://github.com/WangWindow/CANN-BatchMatMulMaxsum --skill precision-pass-wangwindow

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires pandas, and includes scripts (resource) and references (resource) components.

What problem does it solve? When a PyPTO operator on Ascend NPU produces wrong results, developers struggle to determine whether the fault lies in the frontend, a compiler Pass, codegen, or on-device execution. This Skill provides a structured workflow to enable full-chain Pass verification, interpret verification error codes, and pinpoint the exact failing Pass and Op. ## Core Features & Use Cases - Full-chain Pass verification: Configure verify_options and tile_fwk_config.json with PreCheck/PostCheck to validate every compiler Pass, using CodegenPreproc as the authoritative pass/fail criterion. - Op-level fault localization: Run pass_compare.py between a failing Pass and its golden predecessor to generate a CSV of per-Op PASS/FAIL results, then analyze failures by opcode and symbol. - Sync and VF fusion debugging: Detect pipeline synchronization races via enableDebug and binary PIPE_ALL insertion (binary_pipeall_sync.py), then map problem CCE lines back to frontend source with locate_source_line.py. - Use Case: A PyPTO operator fails precision with error 0xB4001U. Enable PreCheck/PostCheck, find CodegenPreproc FAIL, run pass_compare against the previous passing Pass, and identify the exact failing Op to fix. ## Quick Start Ask the assistant to diagnose a PyPTO Pass precision failure by enabling PreCheck/PostCheck verification and running pass_compare to locate the failing Op.

Frequently Asked Questions about precision-pass

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I locate a failing Pass in PyPTO precision verification?▼

Enable PreCheck and PostCheck in tile_fwk_config.json plus verify_options with enable_pass_verify, then rerun the operator. Only the final CodegenPreproc Pass result matters; if it fails, run pass_compare.py against the previous passing Pass to find the failing Op.

What does PyPTO error code 0xB4001U mean?▼

Error 0xB4001U is VERIFY_RESULT_MISMATCH, indicating a frontend or Pass-level precision mismatch. If it appears at tensor_graph stage it is a frontend issue; if tied to a specific Pass, use PreCheck/PostCheck verification and pass_compare to localize it.

How do I use pass_compare.py to find the problem Op?▼

Run pass_compare.py with --p specifying the failed Pass and the golden Pass, plus --verify_path pointing to the verification data directory. It outputs a CSV with per-Op PASS/FAIL results that you can aggregate by opcode and symbol to identify the failing Op.

Why does precision still fail when all PyPTO Passes pass?▼

If CodegenPreproc passes but precision is still wrong, the cause is likely a pipeline synchronization race or VF fusion issue. Enable enableDebug in insert_sync.h to confirm, then use binary_pipeall_sync.py to bisect CCE files and lines for missing pipe_barrier calls.

What environment variables are required for PyPTO Pass verification?▼

Set ASCEND_WORK_PATH for log output, ASCEND_GLOBAL_LOG_LEVEL to 0 for debug logs, and TILE_FWK_DEVICE_ID when running on NPU. Verification also requires torch version 2.1.0 or higher, otherwise error 0xB0001U occurs.

When should intermediate Pass failures be ignored in PyPTO verification?▼

Intermediate Passes such as ReplaceTensor or ProcessAtomic may report VERIFY_RESULT_MISMATCH as false positives. Only the final CodegenPreproc Pass result is authoritative; if it passes, the Pass layer is precision-correct and no further Pass debugging is needed.

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