---
id: pr-cccl-cub-6915
repo: NVIDIA/cccl
pr: 6915
title: Remove need for hardcoded `LevelT` for histogram in c.parallel and cuda.compute
author: NaderAlAwar
date: '2025-12-12'
url: https://github.com/NVIDIA/cccl/pull/6915
source_category: upstream-code
architectures:
- sm100
tags:
- sm100
techniques: []
hardware_features:
- blackwell
kernel_types: []
languages:
- cuda-cpp
captured_at: '2026-05-16'
status: merged
merge_sha: 25b95d426f10bdde9d26507c46c07c6160432d9e
inclusion_reason: Search-matched CUDA kernel optimization PR; materialize diff/source before synthesis.
changed_paths:
- c/parallel/include/cccl/c/histogram.h
- c/parallel/src/histogram.cu
- c/parallel/test/test_histogram.cpp
- cub/cub/device/dispatch/dispatch_histogram.cuh
- cub/cub/device/dispatch/kernels/kernel_histogram.cuh
- python/cuda_cccl/tests/compute/examples/histogram/histogram_even_basic.py
- python/cuda_cccl/tests/compute/examples/histogram/histogram_object.py
- python/cuda_cccl/tests/compute/test_histogram.py
artifact_dir: evidence/pull-bundles/cccl-cub/gh-6915
head_ref_oid: 79340f458767143263d1876a1831f4364c5a3634
---
# Remove need for hardcoded `LevelT` for histogram in c.parallel and cuda.compute

- Repository: `NVIDIA/cccl`
- PR: [6915](https://github.com/NVIDIA/cccl/pull/6915)
- 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/histogram.h`
- `c/parallel/src/histogram.cu`
- `c/parallel/test/test_histogram.cpp`
- `cub/cub/device/dispatch/dispatch_histogram.cuh`
- `cub/cub/device/dispatch/kernels/kernel_histogram.cuh`
- `python/cuda_cccl/tests/compute/examples/histogram/histogram_even_basic.py`
- `python/cuda_cccl/tests/compute/examples/histogram/histogram_object.py`
- `python/cuda_cccl/tests/compute/test_histogram.py`

## Evidence Bundle

`evidence/pull-bundles/cccl-cub/gh-6915`
