# ROCm Documentation has moved to docs.amd.com

ROCm Glossary

host, host cpu : Executes the HIP runtime API and is capable of initiating kernel launches to one or more devices.

default device : Each host thread maintains a default device. Most HIP runtime APIs (including memory allocation, copy commands, kernel launches) do not use accept an explicit device argument but instead implicitly use the default device. The default device can be set with hipSetDevice.

active host thread - the thread which is running the HIP APIs

completion_future becomes ready, “Completes”.

HIP-Clang - Heterogeneous AMDGPU Compiler, with its capability to compile HIP programs on AMD platform (https://github.com/RadeonOpenCompute/llvm-project).

ROCclr- a virtual device interface that compute runtimes interact with different backends such as ROCr on Linux or PAL on Windows.

The ROCclr (https://github.com/ROCm-Developer-Tools/ROCclr) is an abstraction layer allowing runtimes to work on both OSes without much


hipify tools - tools to convert CUDA(R) code to portable C++ code (https://github.com/ROCm-Developer-Tools/HIPIFY).

hipconfig - tool to report various configuration properties of the target platform.

nvcc - nvcc compiler, do not capitalize.

ROCr ROCm runtime 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 ROCK 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.

HCC (Heterogeneous Compute Compiler) : HCC is an Open Source, Optimizing C++ Compiler for Heterogeneous Compute. It supports heterogeneous offload to AMD APUs and discrete GPUs via HSA enabled runtimes and drivers.It is based on Clang, the LLVM Compiler Infrastructure and the ‘libc++’ C++ standard library.The goal is to implement a compiler that takes a program that conforms to a parallel programming standard such as C++ AMP, HC, C++ 17 ParallelSTL, or OpenMP, and transforms it into the AMD GCN ISA.

In the AMD ROCM v3.5 release, the HCC compiler is deprecated and HIP-Clang compiler is introduced for compiling HIP programs


Accelerator Modes Supported:
  • HC C++ API

  • HIP

  • C++AMP

  • C++ Parallel STL

  • OpenMP

HIP (Heterogeneous Interface for Portability) : Heterogeneous Interface for Portability is a C++ runtime API and kernel language that allows developers to create portable applications that can run on AMD and other GPU’s. It provides a C-style API and a C++ kernel language. The first big feature available in the HIP is porting apps that use the CUDA Driver API.

OpenCL : Open Computing Language (OpenCL) is a framework for writing programs that execute across heterogeneous platforms consisting of central processing units (CPUs), graphics processing units (GPUs), digital signal processors (DSPs), field-programmable gate arrays (FPGAs) and other processors or hardware accelerators. OpenCL provides a standard interface for parallel computing using task- and data-based parallelism.The programming language that is used to write compute kernels is called OpenCL C and is based on C99,[16] but adapted to fit the device model in OpenCL. OpenCL consists of a set of headers and a shared object that is loaded at runtime. As of 2016 OpenCL runs on Graphics processing units, CPUs with SIMD instructions, FPGAs, Movidius Myriad 2, Adapteva epiphany and DSPs.

PCIe Platform Atomics : PCI Express (PCIe) was developed as the next generation I/O system interconnect after PCI, designed to enable advanced performance and features in connected devices while remaining compatible with the PCI software environment. Today, atomic transactions are supported for synchronization without using an interrupt mechanism. In emerging applications where math co-processing, visualization and content processing are required, enhanced synchronization would enable higher performance.

Queue : A Queue is a runtime-allocated resource that contains a packet buffer and is associated with a packet processor. The packet processor tracks which packets in the buffer have already been processed. When it has been informed by the application that a new packet has been enqueued, the packet processor is able to process it because the packet format is standard and the packet contents are self-contained – they include all the necessary information to run a command. A queue has an associated set of high-level operations defined in “HSA Runtime Specification” (API functions in host code) and “HSA Programmer Reference Manual Specification” (kernel code).

HSA (Heterogeneous System Architecture) : HSA provides a unified view of fundamental computing elements. HSA allows a programmer to write applications that seamlessly integrate CPUs (called latency compute units) with GPUs (called throughput compute units), while benefiting from the best attributes ofeach. HSA creates an improved processor design that exposes the benefits and capabilities of mainstream programmable compute elements, working together seamlessly.HSA is all about delivering new, improved user experiences through advances in computing architectures that deliver improvements across all four key vectors: improved power efficiency; improved performance; improved programmability; and broad portability across computing devices.For more on HSA.

AQL Architectured Queueing Language : The Architected Queuing Language (AQL) is a standard binary interface used to describe commands such as a kernel dispatch. An AQL packet is a user-mode buffer with a specific format that encodes one command. AQL allows agents to build and enqueue their own command packets, enabling fast, low-power dispatch. AQL also provides support for kernel agent queue submissions: the kernel agent kernel can write commands in AQL format.