Heterogeneous System Architecture (HSA) is a cross-vendor set of hardware specifications that allow for the integration of central processing units and graphics processors on the same bus, with shared memory and shared tasks. The HSA is being developed by the HSA Foundation, which includes (among many others) AMD and ARM. The platform’s stated aim is to reduce communication latency between CPUs, GPUs and other compute devices, and make these various devices more compatible from a programmer’s perspective.
The shared memory architecture allows fine-grained data-sharing between all processors on the chip.
The shared task architecture allows each processor to spawn tasks, including the GPU giving tasks to the CPU.