A Modern Primer on Processing in Memory

Understand

This paper discusses recent research that aims to enable computation close to data, an approach we broadly call processing-in-memory (PIM).

• PIM places computation mechanisms in or near where the data is stored (i.e., inside memory chips or modules, in the logic layer of 3D-stacked memory, in the memory controllers, in storage devices or chips), so that data movement between the computation units and memory/storage units is reduced or eliminated.
• While the general idea of PIM is not new, we discuss motivating trends in applications as well as memory circuits and technology that greatly exacerbate the need for enabling it in modern computing systems.
• We examine at least two promising new approaches to designing PIM systems to accelerate important data-intensive applications: (1) processing-using-memory, which exploits fundamental analog operational principles of memory chips to perform massively-parallel operations in-situ in memory, (2) processing-near-memory, which exploits different logic and memory integration technologies (e.g., 3D-stacked memory technology) to place computation logic close to memory circuitry, and thereby enable high-bandwidth, low-energy, and low-latency access to data.