Collaborative Research: PPoSS: LARGE: Unifying Software and Hardware to Achieve Performant and Scalable Frictionless Parallelism in the Heterogeneous Future

从手机到超级计算机，利用并行性对于充分利用计算机系统至关重要。因此，它是当今大多数应用程序所固有的，并且随着时间的推移变得越来越重要，尤其是在硬件变得更加异构的情况下。然而，编写高效且高性能的并行应用程序仍然是一个严峻的挑战。目前，实现高生产率和高性能需要多名专家。该项目试图将其简化为普通程序员。这个问题通常只沿着两条线中的一条来处理，“理论向下”，关注高级并行语言以及并行算法的理论和实践，或者“架构向上”，关注从硬件开始的多层抽象的重新思考。该项目的核心新颖之处是：(1)统一这两种方法，结合它们的优势以减少编写高性能并行程序所需的专业知识，以及(2)开发能够利用异构硬件的集成技术。实现这些新特性需要设计一种“全栈”方法来实现跨硬件/软件堆栈的并行性和创新性。该项目的影响是：(1)开发了大大简化并行编程的技术，包括异构机器，将其置于普通程序员的范围内；(2)开发了系统和教育材料，将该技能教授给更广泛的受众，包括研究机构的学生。该项目的技术策略是通过一系列程序和目标平台的硬件/软件功能的中间表示（ir），将高级并行语言（允许对程序并行性进行清晰的表达和分析）连接到异构的、可扩展的硬件（使用fpga建模）。这些表示的设计将被调整为避免信息丢失（在编译器/运行时/操作系统/硬件堆栈上下传递），这些信息丢失目前阻碍了所有级别的优化。高级并行语言的一种新的编译模型正在开发中，它广泛地利用了现代编译器技术，但也避免了并行结构的“过早降低”，以及硬件和低级软件特性的“过早抽象”。正在制定基准，以衡量该方法的有效性。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Exploiting parallelism is essential to making full use of computer systems, from phones to supercomputers. It is thus intrinsic to most applications today, and is becoming increasingly so with time, especially as hardware becomes more heterogeneous. Programming effective and performant parallel applications remains a serious challenge, however. Achieving both high productivity and high performance currently requires multiple experts. The project seeks to reduce this to an ordinary programmer. This problem is often approached along only one of two lines, "theory down", focusing on high-level parallel languages and the theory and practice of parallel algorithms, or "architecture up", focusing on rethinking abstractions at multiple layers, starting with the hardware. The project’s core novelties are (1) to unify these two approaches, combining their strengths to reduce the expertise needed to write performant parallel programs, and (2) to develop integrated techniques that can enable taking advantage of heterogeneous hardware. Realizing these novelties will require designing a "full-stack" approach to parallelism and innovation across the hardware/software stack. The project's impacts are (1) the development of techniques that dramatically simplify parallel programming, including for heterogeneous machines, putting it into the purview of the ordinary programmer, and (2) the development of systems and educational materials to teach this skill to broader audiences including students at the researchers' institutions.The technical strategy of the project is to bridge high-level parallel languages, which allow clean expression and analysis of program parallelism, to heterogeneous, extensible hardware (modeled using FPGAs) through an integrated series of intermediate representations (IRs) of a program and of the hardware/software capabilities of the target platform. The design of these representations will be geared to avoid the information loss (going both up and down the compiler/runtime/OS/hardware stack) that currently hampers optimization at all levels. A new compilation model for high-level parallel languages is being developed that extensively leverages modern compiler technology, but also avoids "premature lowering" of parallel constructs, and "premature abstraction" of hardware and low-level software features. Benchmarks are beinge developed to measure the effectiveness of the approach.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.