Extending a Message Passing Runtime to Support Partitioned, Global Logical Address Spaces

Abstract

Partitioned Global Address Space (PGAS) parallel programming models can provide an efficient mechanism for managing shared data stored across multiple nodes in a distributed memory system. However, these models are traditionally directly addressed and, for applications with loosely-structured or sparse data, determining the location of a given data element within a PGAS can incur significant overheads. Applications incur additional overhead from the network latency of lookups from remote location resolution structures. Further, for large data, caching such structures locally incurs space and coherence overheads that can limit scaling. We observe that the matching structures used by implementations of the Message Passing Interface (MPI) establish a separation between incoming data writes and the location where data will be stored. In this work, we investigate extending such structures to add a layer of indirection between incoming data reads and the location from which data will be read, effectively extending PGAS models with logical addressing.