Porting a Program from C to HPVM-C

The following represents the required steps to port a regular C program into an HPVM program with HPVM-C. These steps are described at a high level; for more detail, please see hpvm-cava provided in general benchmarks. For a list of all supported HPVM-C directives, see the HPVM-C Specs.

• Separate the computation that will become a kernel into its own (leaf node) function and add the attributes and target hint.

• Create a level 1 wrapper node function that will describe the thread-level parallelism (for the GPU). The node will:

  • Use the createNode[ND]() method to create a kernel node and specify how many threads will execute it.

  • Bind its arguments to the kernel arguments.

• If desired, create a level 2 wrapper node function which will describe the threadblock-level parallalism (for the GPU). This node will:

  • Use the createNode[ND]() method to create a level 1 wrapper node and specify how many threadblocks will execute it.

  • Bind its arguments to its child node’s arguments.

• A root node function that creates all the top-level wrapper nodes, binds their arguments, and connects their edges.

  • Each root node represents a DFG.

• All the above node functions have the combined arguments of all the kernels that are nested at each level.

• The host code will have to include the following:

  • Initialize the HPVM runtime using the init() method.

  • Create an argument struct for each DFG and assign its member variables.

  • Add all the memory that is required by the kernel into the memory tracker.

  • Launch the DFG by calling the launch() method on the root node function, and passing the corresponding argument struct.

  • Wait for the DFG to complete execution.

  • Read out any generated memory using the request_mem() method.

  • Remove all the tracked memory from the memory tracker.