Collaborative Research: SHF: Medium: Co-Optimizing Computation and Data Transformations for Sparse Tensors

协作研究：SHF：中：稀疏张量的协同优化计算和数据转换

• 批准号: 2107556
• 负责人: Mary Hall
• 金额: $ 43万
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-01-01 至 2025-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2107556&HistoricalAwards=false
• 关键词: Collaborative; Research; SHF; Medium; Co

Sparse tensor computations are central to important applications including computer-assisted drug design, fraud detection, and national security. Timely execution of these applications improves user productivity and reduces the energy consumption associated with each execution. Sparse computations are characterized as having inputs where many or most values are zero. To avoid the inefficiency of storing and computing on zero-valued data, applications only store the nonzeros, with auxiliary data structures to recover their locations. As a result, sparse tensor computations exhibit unpredictable memory-access patterns that include indirection through the auxiliary data structures. Consequently, on today’s computer architectures, performance of sparse tensor computations is completely dominated by the movement of data, through the memory system and across nodes. Data movement is expensive both in terms of execution time and energy expenditure. Optimizing data movement of sparse tensor computations as high-performance architectures have become increasingly diverse — conventional parallel architectures, graphics processors used as parallel accelerators and complex memory systems — creates a performance and productivity challenge for software developers who end up writing low-level architecture-specific code for each platform. The proposed approach simultaneously optimizes how data is organized in memory, how the computation is structured to access the data in a way that reduces data movement, and how the computation and data movement make best use of features of the hardware architectures. Since the nonzero structure of the data is unknown until program execution, the approach also examines runtime information in its decisions. The resulting co-optimization strategy enables a cohesive approach for iteratively making scheduling and data representation transformation decisions for a wide range of sparse computations and incorporating runtime adaptations.This project is developing a programming framework that permits high-level specification of a sparse computation and optimizes it to reduce data movement. It composes data representations, data layouts and storage mappings, and parallel schedules for sparse computations. It employs data dependencies, runtime information, and architecture features to fully bind the final generated code. This approach is intended to enable handling sparse tensor computations with dependences such as sparse triangular solve and many other solvers for systems of linear equations, applying reorderings such as Morton ordering on sparse tensors, and late binding of sparse tensor data representations. The novel and most significant aspects of the research include: (1) composable schedule and data transformations, including data layout transformations and storage mapping; (2) inspector synthesis for runtime data transformations between data representations, layouts, and storage mappings, which are composed with external functions; (3) support for data-dependent tensor computations; and, (4) framework abstractions deployed in the MLIR/LLVM compiler.The researchers are strongly committed to broadening participation in computing and have comprehensive plans to engage the underrepresented groups.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.

稀疏张量计算是重要应用的核心，包括计算机辅助药物设计，欺诈检测和国家安全。及时执行这些应用程序可以提高用户的工作效率，并减少与每次执行相关的能耗。稀疏计算的特征在于具有许多或大多数值为零的输入。 为了避免在零值数据上存储和计算的低效率，应用程序只存储非零值数据，并使用辅助数据结构来恢复它们的位置。 因此，稀疏张量计算表现出不可预测的内存访问模式，包括通过辅助数据结构的间接访问。 因此，在当今的计算机架构上，稀疏张量计算的性能完全由数据通过存储器系统和跨节点的移动所支配。数据移动在执行时间和能量消耗方面都是昂贵的。随着高性能架构变得越来越多样化（传统的并行架构、用作并行加速器的图形处理器和复杂的内存系统），优化稀疏张量计算的数据移动对最终为每个平台编写低级别架构特定代码的软件开发人员带来了性能和生产力挑战。所提出的方法同时优化了如何在内存中组织数据，如何构造计算以减少数据移动的方式访问数据，以及计算和数据移动如何最好地利用硬件架构的功能。由于数据的非零结构在程序执行之前是未知的，因此该方法还在其决策中检查运行时信息。 由此产生的协同优化策略，使一个有凝聚力的方法，迭代地作出调度和数据表示的转换决策，为广泛的稀疏计算，并纳入运行时adaptations.This项目正在开发一个编程框架，允许高层次的规范稀疏计算和优化，以减少数据移动。 它包括数据表示、数据布局和存储映射，以及用于稀疏计算的并行调度。 它使用数据依赖关系、运行时信息和架构特性来完全绑定最终生成的代码。这种方法旨在能够处理具有依赖关系的稀疏张量计算，例如稀疏三角求解和线性方程组的许多其他求解器，对稀疏张量应用重新排序，例如Morton排序，以及稀疏张量数据表示的后期绑定。 该研究的新颖和最重要的方面包括：（1）可组合的调度和数据转换，包括数据布局转换和存储映射;（2）用于数据表示、布局和存储映射之间的运行时数据转换的检查器合成，这些转换与外部函数组合在一起;（3）支持依赖于数据的张量计算;并且，在本发明中，（4）MLIR中部署的框架抽象; LLVM编译器。研究人员坚定地致力于扩大对计算的参与，并制定了全面的计划来吸引代表性不足的群体。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准。

项目成果

Code Synthesis for Sparse Tensor Format Conversion and Optimization

稀疏张量格式转换和优化的代码综合

• 发表时间: 2023
• 期刊: International Symposium on Code Generation and Optimization
• 作者: Popoola, Tobi;Zhao, Tuowen;St. George, Aaron;Bhetwal, Kalyan;Strout, Michelle;Hall, Mary;Olschanowsky, Catherine
• 通讯作者: Olschanowsky, Catherine

Polyhedral Specification and Code Generation of Sparse Tensor Contraction with Co-iteration

• DOI: 10.1145/3566054
• 发表时间: 2022-08
• 期刊: ACM Transactions on Architecture and Code Optimization
• 影响因子: 1.6
• 作者: Tuowen Zhao;Tobi Popoola;Mary W. Hall;C. Olschanowsky;M. Strout

Runtime Composition of Iterations for Fusing Loop-carried Sparse Dependence

用于融合循环携带稀疏依赖的迭代的运行时组合

• DOI: 10.1145/3581784.3607097
• 发表时间: 2023
• 期刊: ACM
• 作者: Cheshmi, Kazem;Strout, Michelle;Mehri Dehnavi, Maryam
• 通讯作者: Mehri Dehnavi, Maryam