Accelerating intercommunication in highly parallel systems

Abstract

Every HPC system consists of numerous processing nodes interconnect using a number of different interprocess communication protocols such as Messaging Passing Interface (MPI) and Global Arrays (GA). Traditionally, research has focused on optimizing these protocols and identifying the most suitable ones for each system and/or application. Recently, there has been a proposal to unify the primitive operations of the different inter-processor communication protocols through the Portals library. Portals offer a set of low-level communication routines which can be composed in order to implement the functionality of different intercommunication protocols. However, Portals modularity comes at a performance cost, since it adds one more layer in the actual protocol implementation. This work aims at closing the performance gap between a generic and reusable intercommunication layer, such as Portals, and the several monolithic and highly optimized intercommunication protocols. This is achieved through the development of a novel hardware offload engine efficiently implementing the basic Portals' modules. Our innovative system is up to two2 orders of magnitude faster than the conventional software implementation of Portals' while the speedup achieved over the conventional monolithic software implementations of MPI and GAs is more than an order of magnitude. The power consumption of our hardware system is less than 1/100th of what a low-power CPU consumes when executing the Portal's software while its silicon cost is less than 1/10th of that of a very simple RISC CPU. Moreover, our design process is also innovative since we have first modeled the hardware within an untimed virtual prototype which allowed for rapid design space exploration; then we applied a novel methodology to transform the untimed description into an efficient timed hardware description, which was then transformed into a hardware netlist through a High-Level Synthesis (HLS) tool.