Proxics: an efficient programming model for far memory accelerators

TL;DR

Proxics introduces a lightweight, portable programming model for near-data processing accelerators based on OS abstractions, optimized for hardware with limited processing power and designed to reduce memory bandwidth.

Contribution

It proposes a novel, efficient implementation of OS-like abstractions for NDP accelerators, enabling portable programming and emphasizing low-latency communication.

Findings

Demonstrated benefits over CPU-only implementations.

Showed effectiveness with various memory access patterns.

Highlighted the importance of efficient communication channels.

Abstract

The use of disaggregated or far memory systems such as CXL memory pools has renewed interest in Near-Data Processing (NDP): situating cores close to memory to reduce bandwidth requirements to and from the CPU. Hardware designs for such accelerators are appearing, but there lack clean, portable OS abstractions for programming them. We propose a programming model for NDP devices based on familiar OS abstractions: virtual processors (processes) and inter-process communication channels (like Unix pipes). While appealing from a user perspective, a naive implementation of such abstractions is inappropriate for NDP accelerators: the paucity of processing power in some hardware designs makes classical processes overly heavyweight, and IPC based on shared buffers makes no sense in a system designed to reduce memory bandwidth. Accordingly, we show how to implement these abstractions in a lightweight and efficient manner by exploiting compilation and interconnect protocols. We demonstrate them with a real hardware platform runing applications with a range of memory access patterns, including bulk memory operations, in-memory databases and graph applications. Crucially, we show not only the benefits over CPU-only implementations, but also the critical importance of efficient, low-latency communication channels between CPU and NDP accelerators, a feature largely neglected in existing proposals.