SI2-SSI: Collaborative Proposal: Performance Application Programming Interface for Extreme-Scale Environments (PAPI-EX)

现代高性能计算 (HPC) 系统的规模和复杂性不断增加。在这些日益复杂的环境中测量应用程序性能的工具还必须增加其测量的丰富性，以深入了解软件和硬件交互日益复杂的方式。 PAPI 性能监控库为所有现代 CPU 和其他一些感兴趣的组件（分散在芯片和系统中）上可用的硬件性能计数器提供了清晰、可移植的接口。经过广泛部署和广泛使用，PAPI 已成为基础软件基础设施，不仅适用于科学计算社区，也适用于 HPC 的许多行业用户。 但过去几年处理器和系统设计发生的根本性变化给 PAPI 和整个 HPC 软件基础设施带来了新的挑战。 PAPI-EX 项目集成了来自政府和行业研究投资的关键 PAPI 增强功能，重点关注处理器和系统设计更改，这些更改预计将出现在通往百亿亿次计算的每个超大规模平台中。PAPI-EX 的主要影响是 PAPI 库重要性的直接影响。 15 年来，PAPI 一直被工具开发商、主要国家 HPC 中心、系统供应商和应用程序开发商广泛使用。 PAPI-EX 建立在这个基础上。作为重要的研究基础设施，PAPI-EX项目使得PAPI在面对新系统设计和规模的革命性变化时能够继续发挥其重要作用。在加强发现和教育方面，与 PAPI-EX 合作的合作伙伴包括 NSF 计算中心、主要工具开发商、主要系统供应商和个人社区领袖，这个多元化的团体将有助于促进培训课程、有针对性的研讨会以及国家和国际会议上的小型研讨会。最后，许多主要系统供应商对 PAPI 的积极推广意味着 PAPI 以及 PAPI-EX 将继续在许多领域为政府和行业带来重大利益。PAPI-EX 解决了当前和未来多核 CPU 的核心共享各种性能关键资源（也称为“核心间”资源）的硬件环境，包括电源管理、片上网络、内存层次结构和核心之间的内存控制器。无法管理这些“核心间”资源的争用已经成为整体应用程序性能的主要拖累。因此，缺乏在低级别揭示这些资源的实际行为的能力，对于许多性能工具（例如，TAU、HPCToolkit、Open|SpeedShop、Vampir、Scalasca、CrayPat、Active Harmony 等）的用户来说已经成为一个很大的问题。 PAPI-EX 增强和扩展了 PAPI，以解决这一关键问题，并使其在 HPC 性能优化中发挥其既定的作用。因此，PAPI-EX 的目标如下： (1) 开发共享硬件计数器支持，包括系统范围和核心间测量； (2) 为基于数据流的运行时系统提供支持； (3) 创建采样接口来记录具有相关上下文的性能数据流； (4) 将用于基于文本的应用程序性能分析的易于使用的工具与 PAPI 高级 API 的更新相结合，创建一个基本的“开箱即用”工具。仪器仪表 API。

Modern High Performance Computing (HPC) systems continue to increase in size and complexity. Tools to measure application performance in these increasingly complex environments must also increase the richness of their measurements to provide insights into the increasingly intricate ways in which software and hardware interact. The PAPI performance-monitoring library has provided a clear, portable interface to the hardware performance counters available on all modern CPUs and some other components of interest (scattered across the chip and system). Widely deployed and widely used, PAPI has established itself as fundamental software infrastructure, not only for the scientific computing community, but for many industry users of HPC as well. But the radical changes in processor and system design that have occurred over the past several years pose new challenges to PAPI and the HPC software infrastructure as a whole. The PAPI-EX project integrates critical PAPI enhancements that flow from both governmental and industry research investments, focusing on processor and system design changes that are expected to be present in every extreme scale platform on the path to exascale computing.The primary impact of PAPI-EX is a direct function of the importance of the PAPI library. PAPI has been in predominant use by tool developers, major national HPC centers, system vendors, and application developers for over 15 years. PAPI-EX builds on that foundation. As important research infrastructure, the PAPI-EX project allows PAPI to continue to play its essential role in the face of the revolutionary changes in the design and scale of new systems. In terms of enhancing discovery and education, the list of partners working with PAPI-EX includes NSF computing centers, major tool developers, major system vendors, and individual community leaders, and this diverse group will help facilitate training sessions, targeted workshops, and mini-symposia at national and international meetings. Finally, the active promotion of PAPI by many major system vendors means that PAPI, and therefore PAPI-EX, will continue to deliver major benefits for government and industry in many domains.PAPI-EX addresses a hardware environment in which the cores of current and future multicore CPUs share various performance-critical resources (a.k.a., 'inter-core' resources), including power management, on-chip networks, the memory hierarchy, and memory controllers between cores. Failure to manage contention for these 'inter-core' resources has already become a major drag on overall application performance. Consequently, the lack of ability to reveal the actual behavior of these resources at a low level, has become very problematic for the users of the many performance tools (e.g., TAU, HPCToolkit, Open|SpeedShop, Vampir, Scalasca, CrayPat, Active Harmony, etc.). PAPI-EX enhances and extends PAPI to solve this critical problem and prepare it to play its well-established role in HPC performance optimization. Accordingly, PAPI-EX targets the following objectives: (1) Develop shared hardware counter support that includes system-wide and inter-core measurements; (2) Provide support for data-flow based runtime systems; (3) Create a sampling interface to record streams of performance data with relevant context; (4) Combine an easy-to-use tool for text-based application performance analysis with updates to PAPI?s high-level API to create a basic, ?out of the box? instrumentation API.