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，以提供对日益复杂的软件和硬件交互方式的洞察。PAPI性能监视库为所有现代cpu和一些其他感兴趣的组件（分散在芯片和系统中）上可用的硬件性能计数器提供了一个清晰的、可移植的接口。PAPI被广泛部署和使用，已成为基础软件基础设施，不仅适用于科学计算社区，也适用于许多HPC行业用户。但是，在过去几年中，处理器和系统设计发生了根本性的变化，这给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的变化，这些变化预计将出现在通往百亿亿级计算的每一个极端规模平台上。PAPI- ex的主要影响直接体现了PAPI库的重要性。PAPI已经被工具开发人员、主要的国家HPC中心、系统供应商和应用程序开发人员使用了超过15年。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PAPI在面对新系统设计和规模的革命性变化时继续发挥其重要作用。在增强发现和教育方面，与PAPI-EX一起工作的伙伴列表包括NSF计算中心、主要工具开发人员、主要系统供应商和个人社区领导，并且这个多样化的小组将帮助促进培训会议、有目标的讲习班和在国家和国际会议上的小型专题讨论会。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解决了一种硬件环境，在这种环境中，当前和未来的多核cpu内核共享各种性能关键资源（也称为“核间”资源），包括电源管理、片上网络、内存层次结构和内核之间的内存控制器。管理这些“核间”资源争用的失败已经成为整个应用程序性能的主要拖累。因此，对于许多性能工具（例如，TAU、HPCToolkit、Open|SpeedShop、vampire、Scalasca、CrayPat、Active Harmony等）的用户来说，缺乏在较低层次上揭示这些资源的实际行为的能力已经成为非常严重的问题。PAPI- ex增强和扩展了PAPI，以解决这一关键问题，并准备在高性能计算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，记录相关上下文的性能数据流；(4)将易于使用的基于文本的应用程序性能分析工具与PAPI的更新相结合？s的高级API来创建基本的，？从盒子里拿出来？仪表的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.