"Pagoda: UPC++ and GASNet-EX for Lightweight Communication and Global Address Space Support"

At SC22 in Dallas, Nov 2022

Tue Nov 15 2:00p CST (DOE Booth #1600 Roundtable Discussion)

Paul H. Hargrove (discussion leader)

The Pagoda project is developing a programming system to support HPC application development using the Partitioned Global Address Space (PGAS) model. The first component is GASNet-EX, a portable, high-performance, global-address-space communication library. The second component is UPC++, a C++ template library. Together, these libraries enable agile, lightweight communication such as arises in irregular applications, libraries and frameworks running on exascale systems.

GASNet-EX is a portable, high-performance communications middleware library which leverages hardware support to implement Remote Memory Access (RMA) and Active Message communication primitives. GASNet-EX supports a broad ecosystem of alternative HPC programming models, including UPC++, Legion, Chapel and multiple implementations of UPC and Fortran Coarrays. GASNet-EX is implemented directly over the native APIs for networks of interest in HPC. The tight semantic match of GASNet-EX APIs to the client requirements and hardware capabilities often yields better performance than competing libraries.

UPC++ provides high-level productivity abstractions appropriate for Partitioned Global Address Space (PGAS) programming such as: remote memory access (RMA), remote procedure call (RPC), support for accelerators (e.g. GPUs), and mechanisms for aggressive asynchrony to hide communication costs. UPC++ implements communication using GASNet-EX, delivering high performance and portability from laptops to exascale supercomputers. HPC application software using UPC++ includes: MetaHipMer2 metagenome assembler, SIMCoV viral propagation simulation, NWChemEx TAMM, and graph computation kernels from ExaGraph.

This round table discussion is an opportunity to meet with the P.I. of the Pagoda project to ask your questions about UPC++ and GASNet-EX.