hipCUB

Note

The published documentation is available at hipCUB in an organized, easy-to-read format, with search and a table of contents. The documentation source files reside in the docs folder of this repository. As with all ROCm projects, the documentation is open source. For more information on contributing to the documentation, see Contribute to ROCm documentation.

hipCUB is a thin wrapper library on top of rocPRIM or CUB. You can use it to port a CUB project into HIP so you can use AMD hardware (and ROCm software).

In the ROCm environment, hipCUB uses the rocPRIM library as the backend. On CUDA platforms, it uses CUB as the backend.

Documentation

Documentation for hipCUB is available at https://rocm.docs.amd.com/projects/hipCUB/en/latest/.

To build our documentation locally, run the following code:

# Go to the hipCUB docs directory
cd hipCUB; cd docs

# Install required pip packages
python3 -m pip install -r .sphinx/requirements.txt

# Build the documentation
python3 -m sphinx -T -E -b html -d _build/doctrees -D language=en . _build/html

# For e.g. serve the HTML docs locally
cd _build/html
python3 -m http.server

Requirements

• Git
• CMake (3.16 or later)
• For AMD GPUs:
  • AMD ROCm software (1.8.0 or later)
    • The HIP-clang compiler (you must, set this as the C++ compiler for ROCm)
  • The rocPRIM library
    • Automatically downloaded and built by the CMake script
    • Requires CMake 3.16.9 or later
• For NVIDIA GPUs:
  • CUDA Toolkit
  • CCCL library (>= 2.4.0)
    • Automatically downloaded and built by the CMake script
    • Requires CMake 3.15.0 or later
• Python 3.6 or higher (for HIP on Windows only; this is only required for install scripts)
• Visual Studio 2019 with Clang support (HIP on Windows only)
• Strawberry Perl (HIP on Windows only)

Optional:

• GoogleTest
• Google Benchmark

GoogleTest and Google Benchmark are automatically downloaded and built by the CMake script.

Build and install

To build and install hipCub, run the following code:

git clone https://github.com/ROCm/hipCUB.git

# Go to hipCUB directory, create and go to the build directory.
cd hipCUB; mkdir build; cd build

# Configure hipCUB, setup options for your system.
# Build options:
#   BUILD_TEST - OFF by default,
#   BUILD_BENCHMARK - OFF by default.
#   DEPENDENCIES_FORCE_DOWNLOAD - OFF by default and at ON the dependencies will be downloaded to build folder,
#
# ! IMPORTANT !
# Set C++ compiler to HIP-aware clang. You can do it by adding 'CXX=<path-to-compiler>'
# before 'cmake' or setting cmake option 'CMAKE_CXX_COMPILER' to path to the compiler.
#
[CXX=hipcc] cmake ../. # or cmake-gui ../.

# To configure hipCUB for Nvidia platforms, 'CXX=<path-to-nvcc>', `CXX=nvcc` or omitting the flag
# entirely before 'cmake' is sufficient
[CXX=nvcc] cmake -DBUILD_TEST=ON ../. # or cmake-gui ../.
# or
cmake -DBUILD_TEST=ON ../. # or cmake-gui ../.
# or to build benchmarks
cmake -DBUILD_BENCHMARK=ON ../.

# Build
make -j4

# Optionally, run tests if they're enabled.
ctest --output-on-failure

# Package
make package

# Install
[sudo] make install

HIP on Windows

Initial support for HIP on Windows is available. You can install it using the provided rmake.py Python script:

git clone https://github.com/ROCm/hipCUB.git
cd hipCUB

# the -i option will install rocPRIM to C:\hipSDK by default
python rmake.py -i

# the -c option will build all clients including unit tests
python rmake.py -c

Using hipCUB

To use hipCUB in a CMake project, we recommended using the package configuration files.

# On ROCm hipCUB requires rocPRIM
find_package(rocprim REQUIRED CONFIG PATHS "/opt/rocm/rocprim")

# "/opt/rocm" - default install prefix
find_package(hipcub REQUIRED CONFIG PATHS "/opt/rocm/hipcub")

...
# On ROCm: includes hipCUB headers and roc::rocprim_hip target
# On CUDA: includes only hipCUB headers, user has to include CUB directory
target_link_libraries(<your_target> hip::hipcub)

Include only the main header file:

#include <hipcub/hipcub.hpp>

Depending on your current HIP platform, hipCUB includes CUB or rocPRIM headers.

Running unit tests

# Go to hipCUB build directory
cd hipCUB; cd build

# To run all tests
ctest

# To run unit tests for hipCUB
./test/hipcub/<unit-test-name>

Using custom seeds for the tests

Go to the hipCUB/test/hipcub/test_seed.hpp file.

//(1)
static constexpr int random_seeds_count = 10;

//(2)
static constexpr unsigned int seeds [] = {0, 2, 10, 1000};

//(3)
static constexpr size_t seed_size = sizeof(seeds) / sizeof(seeds[0]);

(1) Defines a constant that sets how many passes are performed over the tests with runtime-generated seeds. Modify at will.

(2) Defines the user-generated seeds. Each of the elements of the array are used as seeds for all tests. Modify at will. If no static seeds are desired, leave the array empty.

static constexpr unsigned int seeds [] = {};

(3) Never modified this line.

Running benchmarks

# Go to hipCUB build directory
cd hipCUB; cd build

# To run benchmark for warp functions:
# Further option can be found using --help
# [] Fields are optional
./benchmark/benchmark_warp_<function_name> [--size <size>] [--trials <trials>]

# To run benchmark for block functions:
# Further option can be found using --help
# [] Fields are optional
./benchmark/benchmark_block_<function_name> [--size <size>] [--trials <trials>]

# To run benchmark for device functions:
# Further option can be found using --help
# [] Fields are optional
./benchmark/benchmark_device_<function_name> [--size <size>] [--trials <trials>]

Support

Bugs and feature requests can be reported through the GitHub issue tracker.

Contributing

Contributions are most welcome! Learn more at CONTRIBUTING.