---
id: pr-quack-132
repo: Dao-AILab/quack
pr: 132
title: 'RMS Norm Bwd: Optimize for GB200 w/ TMA loads, reload_x, separate output dtype, new launch configs'
author: thakkarV
date: '2026-05-14'
url: https://github.com/Dao-AILab/quack/pull/132
source_category: upstream-code
architectures:
- sm100
- sm90
tags:
- benchmark kernel
- blackwell
- cross-entropy
- cuda kernel
- gemm
- hopper
- norm
- quack
- softmax
techniques:
- async-copy
hardware_features:
- blackwell
- hopper
- tma
kernel_types:
- gemm
- norm
- softmax
languages:
- cuda-cpp
captured_at: '2026-05-16'
status: merged
merge_sha: 4177f18ca650c030b85cb9ab3b6c09f1859ae91d
inclusion_reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.
changed_paths:
- quack/rmsnorm.py
- quack/rmsnorm_config.py
artifact_dir: evidence/pull-bundles/quack/gh-132
head_ref_oid: 98b652a1df5067721d81dc48965ed5075bf5a826
---
# RMS Norm Bwd: Optimize for GB200 w/ TMA loads, reload_x, separate output dtype, new launch configs

- Repository: `Dao-AILab/quack`
- PR: [132](https://github.com/Dao-AILab/quack/pull/132)
- Decision: `Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.`
- Reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.

## Changed Paths

- `quack/rmsnorm.py`
- `quack/rmsnorm_config.py`

## Evidence Bundle

`evidence/pull-bundles/quack/gh-132`
