---
id: pr-cccl-cub-2944
repo: NVIDIA/cccl
pr: 2944
title: fix thread-reduce performance regression
author: fbusato
date: '2024-11-27'
url: https://github.com/NVIDIA/cccl/pull/2944
source_category: upstream-code
architectures:
- sm90
tags:
- benchmark_test
- memory_primitives
- sm90
techniques: []
hardware_features:
- hopper
kernel_types:
- memory
languages:
- cuda-cpp
captured_at: '2026-05-16'
status: merged
merge_sha: 27d8c87eb887feb61b6aadd4557f0444a2681562
inclusion_reason: 'Transfer primitive policy carefully: coalescing, shared-memory staging, partial tiles, and determinism are part of the contract.'
changed_paths:
- cub/cub/thread/thread_operators.cuh
- cub/cub/thread/thread_reduce.cuh
artifact_dir: evidence/pull-bundles/cccl-cub/gh-2944
head_ref_oid: c04dc64df19928cafe39a92e140022d6cd499ecf
---
# fix thread-reduce performance regression

- Repository: `NVIDIA/cccl`
- PR: [2944](https://github.com/NVIDIA/cccl/pull/2944)
- Decision: `Transfer primitive policy carefully: coalescing, shared-memory staging, partial tiles, and determinism are part of the contract.`
- Reason: Transfer primitive policy carefully: coalescing, shared-memory staging, partial tiles, and determinism are part of the contract.

## Changed Paths

- `cub/cub/thread/thread_operators.cuh`
- `cub/cub/thread/thread_reduce.cuh`

## Evidence Bundle

`evidence/pull-bundles/cccl-cub/gh-2944`
