---
id: pr-cccl-cub-8164
repo: NVIDIA/cccl
pr: 8164
title: New tuning API for DeviceScanByKey
author: griwes
date: '2026-04-15'
url: https://github.com/NVIDIA/cccl/pull/8164
source_category: upstream-code
architectures:
- sm100
tags:
- benchmark kernel
techniques: []
hardware_features: []
kernel_types:
- scan
languages:
- cuda-cpp
captured_at: '2026-05-16'
status: merged
merge_sha: 7976e6d174f32f99f485ed3671c3b06426833d8f
inclusion_reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.
changed_paths:
- cub/benchmarks/bench/scan/exclusive/by_key.cu
- cub/cub/device/device_scan.cuh
- cub/cub/device/dispatch/dispatch_scan_by_key.cuh
- cub/cub/device/dispatch/tuning/tuning_scan_by_key.cuh
- cub/test/catch2_test_device_scan_by_key_custom_policy_hub.cu
- cub/test/catch2_test_device_scan_by_key_env.cu
artifact_dir: evidence/pull-bundles/cccl-cub/gh-8164
head_ref_oid: 72fd9eb6644730e3423574fd6ab61fdab7e9c084
---
# New tuning API for DeviceScanByKey

- Repository: `NVIDIA/cccl`
- PR: [8164](https://github.com/NVIDIA/cccl/pull/8164)
- 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/benchmarks/bench/scan/exclusive/by_key.cu`
- `cub/cub/device/device_scan.cuh`
- `cub/cub/device/dispatch/dispatch_scan_by_key.cuh`
- `cub/cub/device/dispatch/tuning/tuning_scan_by_key.cuh`
- `cub/test/catch2_test_device_scan_by_key_custom_policy_hub.cu`
- `cub/test/catch2_test_device_scan_by_key_env.cu`

## Evidence Bundle

`evidence/pull-bundles/cccl-cub/gh-8164`
