We are excited to kick off our summer SAFARI Live Seminars with our first talk next week!

Monday, July 12 at 5:00 pm Zurich time (CEST)

Understanding a Modern Processing-in-Memory Architecture: Benchmarking and Experimental Characterization
Dr. Juan Gomez-Luna, SAFARI Research Group, D-ITET, ETH Zurich

Livestream at 5:00 pm Zurich time (CEST) on YouTube:
https://www.youtube.com/watch?v=D8Hjy2iU9l4

Paper: https://arxiv.org/pdf/2105.03814.pdf
Repository: https://github.com/CMU-SAFARI/prim-benchmarks
Talk slides (pptx) (pdf)

Abstract:
Many modern workloads, such as neural networks, databases, and graph processing, are fundamentally memory-bound. For such workloads, the data movement between main memory and CPU cores imposes a significant overhead in terms of both latency and energy. A major reason is that this communication happens through a narrow bus with high latency and limited bandwidth, and the low data reuse in memory-bound workloads is insufficient to amortize the cost of main memory access. Fundamentally addressing this data movement bottleneck requires a paradigm where the memory system assumes an active role in computing by integrating processing capabilities. This paradigm is known as processing-in-memory (PIM). Recent research explores different forms of PIM architectures, motivated by the emergence of new 3D-stacked memory technologies that integrate memory with a logic layer where processing elements can be easily placed. Past works evaluate these architectures in simulation or, at best, with simplified hardware prototypes. In contrast, the UPMEM company has designed and manufactured the first publicly-available real-world PIM architecture. The UPMEM PIM architecture combines traditional DRAM memory arrays with generalpurpose in-order cores, called DRAM Processing Units (DPUs), integrated in the same chip.

This paper provides the first comprehensive analysis of the first publicly-available real-world PIM architecture. We make two key contributions. First, we conduct an experimental characterization of the UPMEM-based PIM system using microbenchmarks to assess various architecture limits such as compute throughput and memory bandwidth, yielding new insights. Second, we present PrIM (Processing-In-Memory benchmarks), a benchmark suite of 16 workloads from different application domains (e.g., dense/sparse linear algebra, databases, data analytics, graph processing, neural networks, bioinformatics, image processing), which we identify as memory-bound. We evaluate the performance and scaling characteristics of PrIM benchmarks on the UPMEM PIM architecture, and compare their performance and energy consumption to their state-of-the-art CPU and GPU counterparts. Our extensive evaluation conducted on two real UPMEM-based PIM systems with 640 and 2,556 DPUs provides new insights about suitability of different workloads to the PIM system, programming recommendations for software designers, and suggestions and hints for hardware and architecture designers of future PIM systems.

Speaker Bio:
Juan Gomez-Luna is a senior researcher and lecturer in the SAFARI Research Group @ETH Zurich. He received the BS and MS degrees in Telecommunication Engineering from the University of Sevilla, Spain, in 2001, and the PhD degree in Computer Science from the University of Cordoba, Spain, in 2012. Between 2005 and 2017, he was a faculty member of the University of Cordoba. His research interests focus on processing-in-memory, memory systems, heterogeneous computing, and hardware and software acceleration of medical imaging and bioinformatics. He is the lead author of PrIM (https://github.com/CMU-SAFARI/prim-benchmarks), the first publicly-available benchmark suite for a real-world processing-in-memory architecture, and Chai (https://github.com/chai-benchmarks/chai), a benchmark suite for heterogeneous systems with CPU/GPU/FPGA.

Juan Gomez-Luna, Izzat El Hajj, Ivan Fernandez, Christina Giannoula, Geraldo F. Oliveira, and Onur Mutlu,
“Benchmarking a New Paradigm: An Experimental Analysis of a Real Processing-in-Memory Architecture”
Preprint in arXiv, 9 May 2021.
[arXiv preprint]
[PrIM Benchmarks Source Code]
[Slides (pptx) (pdf)]
[Long Talk Slides (pptx) (pdf)]
[Short Talk Slides (pptx) (pdf)]
[SAFARI Live Seminar Slides (pptx) (pdf)]
[SAFARI Live Seminar Video (2 hrs 57 mins)]
[Lightning Talk Video (3 minutes)]