---
id: pr-cccl-cub-3236
repo: NVIDIA/cccl
pr: 3236
title: 'Fix scan / sm90 perf regression '
author: gevtushenko
date: '2025-01-02'
url: https://github.com/NVIDIA/cccl/pull/3236
source_category: upstream-code
architectures:
- sm90
tags:
- arch_pipeline
- benchmark_test
- memory_primitives
- scheduler_autotune
- sm90
techniques:
- autotuning
- pipeline-stages
- tile-scheduling
hardware_features:
- hopper
kernel_types:
- memory
- runtime
- scan
- scheduler
languages:
- cuda-cpp
captured_at: '2026-05-16'
status: merged
merge_sha: b57e065fd1498ed3c62dd02a1bcbf82c084aa6c2
inclusion_reason: 'Transfer primitive policy carefully: coalescing, shared-memory staging, partial tiles, and determinism are part of the contract.'
changed_paths:
- cub/cub/device/dispatch/tuning/tuning_scan.cuh
artifact_dir: evidence/pull-bundles/cccl-cub/gh-3236
head_ref_oid: a3a2ded1d047c12b4644e5f9d764888045e3f9d5
---
# Fix scan / sm90 perf regression 

- Repository: `NVIDIA/cccl`
- PR: [3236](https://github.com/NVIDIA/cccl/pull/3236)
- 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/device/dispatch/tuning/tuning_scan.cuh`

## Evidence Bundle

`evidence/pull-bundles/cccl-cub/gh-3236`
