In-Memory Search With Phase Change Device-Based Ternary Content Addressable Memory
Ling Yang, Rongxuan Zhao, Yi Li, Hao Tong, Yingjie Yu, Xiangshui Miao
Abstract
Here, we proposed an in-memory search prototype based on phase change memory (PCM). First, using the PCM, a highly compact (8F <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) and low-energy (0.3 fJ/bit/search) nonvolatile ternary addressable memory (TCAM) is demonstrated and achieved a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$6.6\times $ </tex-math></inline-formula> energy saving and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$50\times $ </tex-math></inline-formula> cell area saving over the 16T SRAM-TCAM. Thanks to the non-volatility and massive parallelism of the PCM TCAM to computing Hamming distance, the frequent memory access is alleviated, enabling search operation in situ. The prototype shows a high throughput of 256 GB/s in data deduplication application, obtaining more than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$250\times $ </tex-math></inline-formula> energy saving and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$42\times $ </tex-math></inline-formula> improvement in throughput over CPU. Our study provides a low-area-overhead, low-energy, and high-throughput solution for the storage system to perform search in situ.