HClib is a task-based parallel programming model that supports the finish-async, parallel-for, and future-promise parallel programming patterns through both C and C++ APIs. HClib explicitly exposes hardware locality of the hardware, while allowing the programmer to fall back on sane defaults. The HClib runtime is a lightweight, work-stealing, and locality-aware runtime. HClib is not itself an exascale programming system, but is intended to be the intra-node resource management and scheduling component within an exascale programming system, integrating with inter-node communication models such as MPI, UPC++, or OpenSHMEM.

HClib follows your standard cmake and make installation procedure. At its simplest, the manual installation process consists of:

mkdir build; cd build
cmake -DCMAKE_INSTALL_PREFIX=<installation-dir> ..
make install

However, an install.sh script is also provided for your convenience that will build and install HClib. Simply run the script to install:

./install.sh

In addition, the install script will auto-generate a file that can be used to configure your environment (more on that later).

By default, HClib will be installed by the installation script to $PWD/hclib-install. If you would like to use a different installation location, you can override the INSTALL_PREFIX environment variable:

INSTALL_PREFIX=/opt/local ./install.sh

Likewise, if you would like to use different C/C++ compilers other than the system defaults, then you can specify them using the CC and CXX environment variables. For example, if you want to use the Intel compilers:

CC=icc CXX=icpc ./install.sh

After installation, you will need to set the HCLIB_ROOT environment variable to point to your HClib installation directory. You can automatically set this variable after installation by sourcing the hclib_setup_env.sh script generated by install.sh. For example, assuming HClib was installed with INSTALL_PREFIX=/opt/local:

source /opt/local/bin/hclib_setup_env.sh

Few HClib cmake options available are: HCLIB_ENABLE_HWLOC, HCLIB_ENABLE_PRODUCTION, HCLIB_ENABLE_STATS, HCLIB_ENABLE_VERBOSE, HCLIB_PRIVATIZE_C_STD_11, HCLIB_INLINE_FUTURES_ONLY

For example, to enable production setting:

./install.sh -DHCLIB_ENABLE_PRODUCTION=ON

To support unified scheduling on heterogeneous computation and communication resources HClib uses a module system. Loading a given module automatically adds support the the HClib API and runtime for accessing some new resource in HClib. By default, HClib only supports executing parallel programs on multi-core x86 platforms. However, with existing modules this can be extended to include support for GPU execution and communication over MPI, OpenSHMEM, and UPC++.

While you can write a fully functioning HClib program without any additional modules, many of the test programs saved in this repo load the system module. The system module adds basic OS-related routines, such as asynchronous memory allocation and deallocation. If you would like to run any of these basic tests, the instructions below guide you through the process of building and installing the 'system' module.

If install.sh is used to create an HClib installation, the system module will automatically be built and installed. However, if you wish to configure and install HClib manually you will also need to build and install the system module manually. Once you have completed your HClib install, navigate to the hclib/modules/system directory and run:

mkdir build; cd build
cmake -DCMAKE_INSTALL_PREFIX=<installation-dir> ..
make install

Ensure that you have HCLIB_ROOT set in your environment first.

• automake
• gcc >= 4.8.4, or clang >= 3.5 (must support -std=c++11 and -std=c11)

If you are new to HClib then take a look of hclib/tutorial directory. It contains presentations and simple examples that appeared in our past tutorials on HClib. You can follow the README inside sub-directories there to build and run those examples.

The main regression tests for HClib are in the test/c and test/cpp folders. The test_all.sh scripts in each of those folders will automatically build and run all test cases.

As part of the development workflow for HClib, any newly committed code should be checked using standard static checking tools.

In particular, run cppcheck on all modified files. cppcheck is available online at [1]. cppcheck should be run by cd-ing to tools/cppcheck and executing the run.sh script from there (this assumes cppcheck is on your path). Any new errors printed by cppcheck should be addressed before committing.

You should also run astyle on all modified files. astyle is a source code auto-formatter. Simply cd to tools/astyle and execute the run.sh script from there. This assumes you have astyle installed and it is on your path.

[1] https://sourceforge.net/projects/cppcheck/