CSR: Small: Operating System Abstractions for GPU-Accelerated Interactive Applications

在过去十年中，计算密度最显著的提升来自图形处理单元（gpu），而不是中央处理单元（cpu）。不幸的是，当前的操作系统（os）并没有为gpu提供与应用程序期望的其他资源（如cpu、输入设备和文件系统）相同的高级编程抽象。操作系统将gpu隐藏在一个笨拙的ioctl接口后面，将抽象的负担转移到用户库和运行时上。新技术需要新的抽象。像识别手势、脑机接口和音频/视觉接口这样的富接口是高度计算密集型的。由于它们在实时约束下处理大量数据，因此超出了现代cpu的能力。这些工作负载依赖于数据并行算法，使gpu成为加速这些任务的理想资源，但需要某种形式的操作系统支持来确保与用户的安全交互。SymbiOS模型是用于管理交互式、大规模并行设备的内核抽象的基本重组。内核必须充分暴露GPU的硬件细节，以允许程序员利用其巨大的处理能力，但必须隐藏程序员的不便，如CPU和GPU之间的内存不一致。在SymbiOS模型下，gpu被提升为一级计算资源，具有传统操作系统的公平性、隔离性等保证。该项目的目标是为GPU设计和开发操作系统抽象，并实现几个案例研究，包括利用SymbiOS模型在商用GPU硬件上提供实时性能的手势驱动UI。

The most dramatic gains in compute density in the last decade have come from graphics processing units (GPUs) rather than central processing units (CPUs). Unfortunately, current operating systems (OSes) do not provide the same kind of high-level programming abstractions for GPUs that applications expect for other resources like CPUs, input devices, and file systems. OSes hide GPUs behind an awkward ioctl interface, shifting the burden of abstraction onto user libraries and run-times.New technologies require new abstractions. Rich interfaces like recognizing gestures, brain-computer interfaces, and audio/visual interfaces are highly compute-intensive. Because they process voluminous data under real-time constraints, they are beyond the capabilities of modern CPUs. These workloads rely on data-parallel algorithms, making GPUs an ideal resource to accelerate these tasks, but some form of OS support is required to ensure safe interaction with the user.The SymbiOS model is a fundamental reorganization of kernel abstractions for managing interactive, massively parallel devices. The kernel must expose enough of the hardware detail of GPUs to allow programmers to take advantage of their enormous processing capabilities, but must hide programmer inconveniences like memory that is incoherent between the CPU and GPU. Under the SymbiOS model, GPUs are promoted to first-class computing resources, with traditional OS guarantees such as fairness and isolation.The goal of this project is the design and development of OS abstractions for GPUs, and implementation of several case-studies including a gesture-driven UI that leverages the SymbiOS Model to deliver real-time performance on commodity GPU hardware.