HSA获得HSAIL支持

AMD’sHeterogeneous System Architecture (HSA) is the floorplan for its next generation of accelerated processing units (APUs), which combine the CPU and GPU into a common memory environment(see “Unified CPU/GPU Memory Architecture Raises The Performance Bar”)通过缓存共享的虚拟内存（CC-SVM）。原始的APU组合了CPU和GPU内核，但为每种类型的核心保持独特的内存(see “APU Blends Quad Core x86 With 384-Core GPU”)。

OpenCL 2.0 addresses CPU and GPU parallel processing environments(see “OpenCL 2.0, OpenGL 4.4 Officially Released”)。通常，环境为GPU具有独特的地址空间。该模型还用于一些基于FPGA的OPENCL环境(see “How To Put OpenCL Into An FPGA”), but HSA is different because it has a unified memory environment. The Heterogeneous System Architecture Intermediate Language (HSAIL) and associated design environment were developed to take advantage of HSA. Frameworks like OpenCL can generate HSAIL that can run on a virtual machine that targets CPU/GPU cores.

HSAIL divides work into a grid hierarchy(Fig. 1)。像OpenCL一样，程序员定义可以在数据上并行运行的内核。最大的区别在于，Hsail基本上将基于HSA的虚拟机映射到。HSA最终确定器类似于Java虚拟机（JVM）的JIT（即时）汇编。

The HSAIL virtual machine consists of at least one host CPU and an HSA component. The Architected Queue Language (AQL) links the two. The host generates and enqueues AQL packets. The packets incorporate kernels that are executed by the HSA component. A kernel defines a multidimensional cube-shaped grid with a work-group item per grid point. Jobs are dispatched as work groups. They require all data to be available.

AMD would like HSA to be a standard so HSAIL is open, but for now it will take advantage only of AMD’s HSA-based hardware. It may be wishful thinking that Intel would incorporate it, although an integrated CPU/GPU/memory environment has advantages and AMD and Intel have at least agreed upon the x86 instruction set. HSAIL could be applied to an ARM environment. It is interesting to note that ARM is one of the founding members of theHSA Foundationalong with AMD, Samsung, Qualcomm, MediaTek, Imagination, and Texas Instruments.

Another aspect of HSAIL and HSA is Java support(Fig. 2)。Aparapi（并行API）是Java支持并行编程环境的一种方法。它通常将其映射到OpenCL，但可以针对Hsail最终制度。

APARAPI eventually may be replaced byOpenJDK’sProject Sumatra, which brings native parallel programming support to Java. Project Sumatra also could target HSAIL directly.Oracleand AMD are involved with Project Sumatra, so this combination may wind up in production. Support is targeted for Java 9.

Developers can leverage the HSA architecture using the BOLT library from AMD. The C++ template library inspired BOLT, which also has been targeted at OpenCL and C++AMP.

OpenCL和Project Sumatra将仍然是程序员的主要编程环境，但HSA可以提供更好的基础架构。统一的内存体系结构消除了不必要的副本操作，因为可以在CPU和GPU内核之间共享指针。该方法还具有较低的调度开销。

For now, AMD’s hardware will be driving HSAIL development and the software that runs on top of it. In the future, it could be much more.