基于现有 DRAM进行存内计算（线上）
日期：2023/08/24 - 2023/08/24
学术讲座：基于现有 DRAM进行存内计算（线上）
主讲人：高飞, 普林斯顿大学
时间：2023年8月24日（周四）上午10:00
地点: 龙宾楼403会议室 / 飞书会议：675201371
讲座摘要
In-memory computing has long been promised as a solution to the “Memory Wall” problem. Unfortunately, performing computations with memory resources either has relied on emerging memory technologies which are not readily available today or has required additional circuits be added to RAM arrays. So far, the competitive and low-margin nature of the RAM industry has made commercial RAM manufacturers resist adding any additional logic into the existing design. In this talk, we demonstrate methods of in-memory compute with off-the-shelf DRAM chips without any hardware modification, thus make it more realistic and ready-to-use.
We found that specially timed DRAM command sequences lead to undocumented, but also constructive and stable behaviors in DRAM array. We studied and characterized those behaviors with a customized DRAM controller and unmodified DRAM modules from major DRAM vendors. We propose a DRAM command sequence that can open multiple DRAM rows at the same time, thereby enabling bit-line charge sharing. With the charge sharing, we implement intra-subarray row copy and majority-of-three operations. Subsequently, these primitive operations are employed to develop an architecture for arbitrary, massively-parallel, bit-serial computation with off-the-shelf DRAM. Subsequently, additional command sequences are proposed to store fractional value in a DRAM cell. Utilizing fractional value storage, we could enable more modules to perform the in-memory majority operation, increase the stability of the existing in-memory majority operation, and build a state-of-the-art DRAM-based PUF with unmodified DRAM.
主讲人简介
高飞于2017年获得清华大学微电子工程学士学位，并于2019年获得普林斯顿大学计算机与电子工程硕士学位。他目前在普林斯顿大学攻读博士学位，并专注于内存计算和众核异构架构的研究。