4/18/2013 Megan Osfar
Written by Megan Osfar
University of Illinois computer science professor Josep Torrellas has received a High-Impact Paper Award from the ICCD for the paper “FlexRAM: Toward an Intelligent Memory System.” The award was given in recognition of the work being one of the five most-cited papers in the 30-year history of the IEEE’s International Conference on Computer Design (ICCD). The award for this ICCD 1999 paper was presented to Professor Torrellas at ICCD-30, which was recently held in Montreal.
The paper proposed a Processing-in-Memory (PIM; also known as Intelligent Memory) chip and a PIM-based architecture that places many tiny cores in the memory system of an otherwise commodity machine. The memory cores are small, to minimize losses in memory integration, and numerous, to extract high bandwidth. The FlexRAM design was also meant to be general purpose and widely usable: it doesn’t pattern-match any particular algorithm, and the main processor of the machine is left unmodified, which works well for legacy applications.
The FlexRAM paper was co-authored with then graduate students at the University of Illinois Yi Kang, Wei Huang, Seung-Moon Yoo, Diana Keen, Zhenzhou (“Bruce”) Ge, and Vinh Lam. Pratap Pattnaik, who is an IBM Fellow, was also a co-author on the paper. The greater FlexRAM project was a major effort of Torrellas’ research group that lasted several years, and which included the work of about ten graduate students, four Illinois faculty members (Professors Padua, Chien, Reed, and Huang), several visiting scholars (Professors Fraguela, Lee, and Feautrier), and IBM researchers (Drs. Pattnaik, Ekanadham, and Lim).
Although the FlexRAM Project at Illinois has ended, the ideas behind it continue to influence other work. While interest in PIM for consumer products waned during the early 2000s due to the production costs of these specialized systems, Intelligent Memory has remained a desirable memory system within the supercomputer research and development community --- with its emphasis on high chip integration and on reducing the latency and energy losses due to communication.
Due to the compelling ideas behind PIMs and advances in technology, there has been a resurgence of interest in Intelligent Memory from the commercial sector. In the past two years, a number of companies have come out with PIM-like designs. Notably, both Micron and Samsung have announced 3-D integrated circuits that stack multiple memory dies over a logic die, effectively enabling PIM. In particular, Micron’s Hybrid Memory Cube (HMC) chip, announced in 2011, has received considerable publicity. In fact, Intel has stated that it is collaborating with Micron on furthering the development of HMC technology.
Professor Torrellas’ current research focuses on processor, memory, and system technologies and organizations to build novel multiprocessor computer architectures. He is the Director of the Center for Programmable Extreme Scale Computing and the Director of the Illinois-Intel Parallelism Center (I2PC).
Writer: Megan Osfar, Intel-Illinois Parallelism Center, mosfar2 [at] illinois [dot] edu, 217/265-6738.
Contact: Josep Torrellas, Department of Computer Science, torrella [at] illinois [dot] edu, 217/244-4148.