hiCL is a C/C++ and Fortran wrapper that makes it easier to use OpenCL
for scientific computing. Writing an OpenCL code evolves including hundreds
of lines of host code. In scientific computing, host code is usually cumbersome
and very verbose in such a manner scientists would spend more time putting
together the host code rather than focusing on accelerating their workloads
on GPUs or on any other OpenCL capable hardware.
hiCL extensively reduces the need to focus on the host code and offers
a set of functionalities in C/C++ and Fortran to help efficiently exploit
hardware accelerators for scientific computing.
hiCL offers a transparent way to manage memory objects on different
hardware accelerators with different memory models thanks to a set of bitwise
flags.
A paper about hiCL was
published at the
International OpenCL Workshop in Vienna, Austria
on late April 2016.
The following section is a step by step guide that will take you from fetching the source code from the repository branches to running your hiCL first examples on your machine.
The project contains two git main branches: master and develop. The master branch only contains the major releases, and is intended to use the library as is. We recommend to clone from this branch if you would like to use the latest stable version. The releases are tagged on the master branch and each version has a major number and a minor number which are used as the tagging string (.e.g. the first release is tagged 1.0 on the master branch). Cloning the master branch and checking out the latest release can be done as follows:
git clone -b master https://github.com/issamsaid/hiCL.git
If you wish to clone a specific release (here we use the 1.0 release as an example) you may add:
pushd hiCL
git checkout tags/1.0
popd
The following table summarizes the different details about all the
releases of the hiCL library:
| Release number (tag) | Date | Description |
|---|---|---|
| 1.0 | 06/01/2016 | The initial release of the hiCL library |
On the other hand, the develop branch contains the latest builds and is intended to be used by the developers who are willing to contribute or improve the library. To get started, you can clone this branch as follows:
git clone -b develop https://github.com/issamsaid/hiCL.git
The hiCL project has multiple components, each in a subdirectory of the root directory (hiCL):
- The src subdirectory is the C/C++ interface.
- The fortran_interface subdirectory is the Fortran interface.
- The test subdirectory contains the unit tests of the library.
- The doc subdirectory is where the documentation of the library is to be generated.
- The examples includes a set of examples of how to use the library.
The project compilation framework is to be setup using the cmake utility. Depending on your operating system you may choose a specific cmake generator to build the project. As an example, if you wish to build hiCL on Unix based operating systems you can use the following (the rest of the examples in this material are also intended to be used on Unix based systems):
pushd hiCL
mkdir build
pushd build
cmake -G"Unix Makefiles" ../
popd
The current version of hiCL had been tested on various Linux
distributions with the GNU, Cray and Intel compilers.
Nevertheless, if you face issues with other compilers you are kindly invited to report them.
Note that if you are using Cray compilers you have to specify where the
Fortran compiler is wrapped. For example if you are using ftn you have to add:
pushd hiCL
mkdir build
pushd build
cmake -DCMAKE_Fortran_COMPILER=ftn -G"Unix Makefiles" ../
popd
In addition, it is to be noted that hiCL is not yet compatible with the PGI Fortran compiler. We are working on solving this issue.
It goes without saying that hiCL depends on OpenCL.
If your installed OpenCL implementation is not found by our cmake
script, where we try to look for your implementation in the usual install directories, you can help setting it manually as follows:
export OPENCL_INCLUDE_DIR="YOUR_OPENCL_HEADERS_PATH"
export OPENCL_LIBRARY_DIR="YOUR_OPENCL_LIBRARY_PATH"
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:$OPENCL_LIBRARY_DIR
export LIBRARY_PATH=$LIBRARY_PATH:$OPENCL_LIBRARY_DIR
Besides, hiCL uses internally the ulist and urb_tree libraries ( respectively a generic linked list library and a red-black trees generic libraries) in order to track and efficiently manipulate the OpenCL resources. It also relies on the googletest framework for unit testing. Those libraries are automatically downloaded, compiled and installed when building hiCL. Alternatively you can set the path to those libraries if they are already installed on your system as follows:
export ULIST_DIR="YOUR_PATH_TO_ULIST"
export URB_TREE_DIR="YOUR_PATH_TO_URB_TREE"
export GTEST_DIR="YOUR_PATH_TO_GTEST"
To build the hiCL C static library you can run the default Makefile target as follows:
pushd build
make hicl
popd
This Makefile target will build the static library libhiCL.a from the C/C++
source files in the src
subdirectory.
Since this is the default target you can also build the static C library
as follows:
pushd build
make
popd
If you would like to build the Fortran interface additionally, you can do so as follows:
pushd build
make hicl_fortran
popd
This target will build another static library libhiCL_fortran.a from the
Fortran source files present in the
fortran_interface subdirectory. Note that the Fortran interface is only
an additional layer based on the Fortran 2003 standard (ISO/IEC 1539-1:2004(E)),
which generates procedure and derived-type declarations and global variables that are interoperable with C. Therefor, if the C/C++ interface is not built this target will build it as well.
The library comes with a set of unit tests and performance tests to validate the new features. You can check the unit testing directory here. The testing framework is used to thoroughly test hiCL in C/C++ (test/src) and Fortran (test/fortran). The C/C++ interface unit tests are based on top of the googletest Framework). To build all the unit tests, C/C++ and Fortran included, you can invoke the following target:
pushd build
make build_tests
popd
Alternatively make hicl_test will only build the test suit for the C/C++ interface, and make hicl_test_fortran will build the unit tests for the
Fortran interface.
Tests should be written for any new code, and changes should be verified to not
break existing tests before they are submitted for review.
The project comes with a set of C/C++ and Fortran samples that you can browse in the
examples subdirectory.
Those can be built as follows:
pushd build
make build_examples
pupd
Alternatively make c_examples will only build and
install the C/C++ examples, and make fortran_examples will build and install the Fortran examples.
The documentation of the library can be generated, in the doc subdirectory, with the help of doxygen by simply running:
pushd build
make doc
popd
In order to install the hiCL project you can invoke the classic Makefile install target:
pushd build
make install
popd
This target mainly installs the hiCL C/C++ static library in the lib subdirectory on the project root directory. If the Fortran static library, the unit tests binaries and the examples binaries are built, they will be installed
respectively in the lib, test/bin and examples/bin subdirectories.
We use Travis CI for the continuous integration of the hiCL library. The image on the top of the page is a link to the latest build of each branch. A build is launched after each pull request with respect to the Travis CI configuration file (.travis.yml).
In order to use the hiCL C/C++ link your code against libhiCL.a
additionally to the OpenCL library (by adding
-lhiCL -lOpenCL to your linker options),
however if your code is based on Fortran the
latter should linked against both the C/C++ library and the Fortran interface (
with the help of the options -lhiCL_fortran -lhiCL -lOpenCL).
To perform the unit tests you can run:
pushd test
./bin/hicl_test // for C/C++
./bin/hicl_test_fortran // for Fortran
popd
The examples binaries can be browsed in the examples/bin subdirectory.
It is now up to you to read the documentation and check the examples in order
to use hiCL to write your own OpenCL codes for scientific purposes.
Using the library only requires adding few lines to your original code.
To pass some specific build options to the OpenCL compiler one can set the
HICL_BUILD_OPTIONS environment variable as follows:
export HICL_BUILD_OPTIONS="YOUR_OPENCL_BUILD_OPTIONS" // examples: -cl-denorms-are-zero -cl-opt-disable -cl-mad-enable
See the Khronos registry for more OpenCL kernels build options.
We believe that hiCL can be used by scientific programmers very efficiently. We tend to extend the functionalities of the library. For this to do we need your feedbacks and proposals of features and use cases. If you are willing to contribute please visit the contributors guide CONTRIBUTING, or feel free to contact us.
hiCL is a free software licensed under BSD and was put together in a computer science laboratory at the UPMC. The project was initially funded by Total which is acknowledged.
For bug report, feature requests or if you willing to contribute please feel free to contact Issam SAID by dropping a line to [email protected].