This repository includes the user-mode API interfaces and libraries necessary for host applications to launch compute kernels to available HSA Boltzmann kernel agents. Reference source code for the core runtime is also available.

Only the AMD/ATI Fiji(c) family of discrete GPUs are currently supported.

• CPU: Intel(c) Haswell or newer, Core i5, Core i7, Xeon E3 v4 & v5; Xeon E5 v3
• GPU: Fiji ASIC (AMD R9 Nano, R9 Fury and R9 Fury X)

The HSA core runtime source code for Boltzmann is located in the src subdirectory. Please consult the associated README.md file for contents and build instructions.

The packages subdirectory contains the Debian and rpm packages for installing the runtime on Ubuntu and Fedora platforms. These files contain:

• HSA include files to support application development on the HSA runtime for Boltzmann
• A 64-bit version of AMD's HSA core runtime for Boltzmann
• A 64-bit version of AMD's finalizer extension for Boltzmann
• A 64-bit version of AMD's runtime tools library

To install the package on Ubuntu execute the following command:

`dpkg -i hsa-runtime-dev-1.0.0-amd64.deb`

For Fedora execute the following command:

    `rpm -i hsa-runtime-dev-1.0-0.fc22.x86_64.rpm`

The contents are installed in /opt/hsa by default.

The HSA runtime is a thin, user-mode API that exposes the necessary interfaces to access and interact with graphics hardware driven by the AMDGPU driver set and the Boltzmann HSA kernel driver. Together they enable programmers to directly harness the power of AMD discrete graphics devices by allowing host applications to launch compute kernels directly to the graphics hardware.

The capabilities expressed by the HSA Runtime API are:

• Error handling
• Runtime initialization and shutdown
• System and agent information
• Signals and synchronization
• Architected dispatch
• Memory management
• HSA runtime fits into a typical software architecture stack.

The HSA runtime provides direct access to the graphics hardware to give the programmer more control of the execution. Some examples of low level hardware access is the support of one or more user mode queues provides programmers with a low-latency kernel dispatch interface, allowing them to develop customized dispatch algorithms specific to their application.

The HSA Architected Queuing Language is an open standard, defined by the HSA Foundation, specifying the packet syntax used to control supported AMD/ATI Radeon (c) graphics devices. The AQL language supports several packet types, including packets that can command the hardware to automatically resolve inter-packet dependencies (barrier AND & barrier OR packet), kernel dispatch packets and agent dispatch packets.

In addition to user mode queues and AQL, the HSA runtime exposes various virtual address ranges that can be accessed by one or more of the system's graphics devices, and possibly the host. The exposed virtual address ranges either support a fine grained or a coarse grained access. Updates to memory in a fine grained region are immediately visible to all devices that can access it, but only one device can have access to a coarse grained allocation at a time. Ownership of a coarse grained region can be changed using the HSA runtime memory APIs, but this transfer of ownership must be explicitly done by the host application.

Programmers should consult the HSA Runtime Programmer's Reference Manual for a full description of the HSA Runtime APIs, AQL and the HSA memory policy.

The simplest way to check if the kernel, runtime and base development environment are installed correctly is to run a simple sample. A modified version of the vector_copy sample was taken from the HSA-Runtime-AMD repository and added to the ROCR repository to facilitate this. Build the sample and run it, using this series of commands:

cd ROCR-Runtime/sample && make && ./vector_copy

If the sample runs without generating errors, the installation is complete.

• The image extension is currently not supported for discrete GPUs. An image extension library is not provided in the binary package. The standard hsa_ext_image.h extension include file is provided for reference.
• Each HSA process creates and internal DMA queue, but there is a system-wide limit of four DMA queues. The fifths simultaneous HSA process will fail hsa_init() with HSA_STATUS_ERROR_OUT_OF_RESOURCES. To run an unlimited number of simultaneous HSA processes, set the environment variable HSA_ENABLE_SDMA=0.

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