企业官网建设流程全解析

Deep Note:agent/example/kernels/a2/attn_backward_dense_total_tail.py

【免费下载链接】cannbot-skillsCANNBot 是面向 CANN 开发的用于提升开发效率的系列智能体，本仓库为其提供可复用的 Skills 模块。项目地址: https://gitcode.com/cann/cannbot-skills

Open this file only after the short catalog entry confirmed the kernel is relevant.

What this kernel is really for

• the full tail-safe a2 dense attention-backward fusion, not the smaller stage-1 or stage-1+2 teaching variants
• a path that has to survive bothS1andS2tails while keeping the cube/vec/cube bridges stable

Decisions worth copying

• keep both GM workspace bridges on full-tile shapes and pushvalid_m/valid_nhandling to GM boundaries plus vec masks
• keep the stage-1 vec hot path chunk-local instead of reusing the old half-tile story; separate chunk-sized scratch is easier to validate
• if vec scratch growth becomes risky, prefer smaller chunks over borrowing live stage buffers
• reuse delayedk_jon chip for the finalgq += dqk_j @ k_jstage instead of reloading from GM
• promote only the reusedkoperand family toTBuff; leave unrelated families on simpler buffering
• keep tile-levelatomic_add()narrow and expect caller-side zero initialization

Prefer another kernel when

• you want the smallest aligned-only backward reference
• you only need the stage-1 or stage-1+2 intermediate contract

【免费下载链接】cannbot-skillsCANNBot 是面向 CANN 开发的用于提升开发效率的系列智能体，本仓库为其提供可复用的 Skills 模块。项目地址: https://gitcode.com/cann/cannbot-skills