---
id: pr-cccl-cub-7892
repo: NVIDIA/cccl
pr: 7892
title: Reduce warpspeed scan to 256 threads/block on NVHPC
author: bernhardmgruber
date: '2026-03-09'
url: https://github.com/NVIDIA/cccl/pull/7892
source_category: upstream-code
architectures:
- sm100
tags:
- block
techniques:
- warp-specialization
hardware_features: []
kernel_types:
- scan
languages: []
captured_at: '2026-05-16'
status: merged
merge_sha: ed1e14658721d420bec78ceb99df90f72d92a746
inclusion_reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.
changed_paths:
- cub/cub/device/dispatch/tuning/tuning_scan.cuh
artifact_dir: evidence/pull-bundles/cccl-cub/gh-7892
head_ref_oid: b6306b4676a4b746ddb2515299d7eea0b7774de5
---
# Reduce warpspeed scan to 256 threads/block on NVHPC

- Repository: `NVIDIA/cccl`
- PR: [7892](https://github.com/NVIDIA/cccl/pull/7892)
- 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

- `cub/cub/device/dispatch/tuning/tuning_scan.cuh`

## Evidence Bundle

`evidence/pull-bundles/cccl-cub/gh-7892`
