---
id: pr-cccl-cub-8158
repo: NVIDIA/cccl
pr: 8158
title: Let scan tuning policy choose warpspeed or not
author: bernhardmgruber
date: '2026-04-09'
url: https://github.com/NVIDIA/cccl/pull/8158
source_category: upstream-code
architectures:
- sm100
tags:
- scan
- sm100
techniques:
- warp-specialization
hardware_features:
- blackwell
kernel_types:
- scan
languages: []
captured_at: '2026-05-16'
status: merged
merge_sha: cf1a8ef5de8bec9422b1fcb8ab9e1a61968c5547
inclusion_reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.
changed_paths:
- c/parallel/include/cccl/c/scan.h
- c/parallel/src/scan.cu
- c/parallel/src/util/scan_tile_state.cu
- cub/benchmarks/bench/scan/policy_selector.h
- cub/cub/device/device_scan.cuh
- cub/cub/device/dispatch/dispatch_radix_sort.cuh
- cub/cub/device/dispatch/dispatch_scan.cuh
- cub/cub/device/dispatch/kernels/kernel_radix_sort.cuh
- cub/cub/device/dispatch/kernels/kernel_scan.cuh
- cub/cub/device/dispatch/kernels/kernel_scan_warpspeed.cuh
- cub/cub/device/dispatch/kernels/scan_warpspeed_policy.cuh
- cub/cub/device/dispatch/tuning/tuning_radix_sort.cuh
- cub/cub/device/dispatch/tuning/tuning_scan.cuh
- cub/test/catch2_test_device_scan_env.cu
artifact_dir: evidence/pull-bundles/cccl-cub/gh-8158
head_ref_oid: f497303b817839bedf28a09fa9772378852981bb
---
# Let scan tuning policy choose warpspeed or not

- Repository: `NVIDIA/cccl`
- PR: [8158](https://github.com/NVIDIA/cccl/pull/8158)
- 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

- `c/parallel/include/cccl/c/scan.h`
- `c/parallel/src/scan.cu`
- `c/parallel/src/util/scan_tile_state.cu`
- `cub/benchmarks/bench/scan/policy_selector.h`
- `cub/cub/device/device_scan.cuh`
- `cub/cub/device/dispatch/dispatch_radix_sort.cuh`
- `cub/cub/device/dispatch/dispatch_scan.cuh`
- `cub/cub/device/dispatch/kernels/kernel_radix_sort.cuh`
- `cub/cub/device/dispatch/kernels/kernel_scan.cuh`
- `cub/cub/device/dispatch/kernels/kernel_scan_warpspeed.cuh`
- `cub/cub/device/dispatch/kernels/scan_warpspeed_policy.cuh`
- `cub/cub/device/dispatch/tuning/tuning_radix_sort.cuh`
- `cub/cub/device/dispatch/tuning/tuning_scan.cuh`
- `cub/test/catch2_test_device_scan_env.cu`

## Evidence Bundle

`evidence/pull-bundles/cccl-cub/gh-8158`
