Overview

The knowledge center provides tools and infrastructures to support research on Chip MultiProcessors (CMP) in Israel. It facilitates collaboration among researchers from separate scientific communities, including architecture, circuits, micro-architecture, VLSI, operating systems, parallel and distributed computing, and computer networks. The center thus enables the multi-disciplinary research required for progress in the area of CMP.

The Knowledge Center is funded in part by the Israeli Ministry of Science, Culture and Sport.

The Knowledge Center is managed by:

Outreach

In February 2009, we held a workshop on Multicore Day: The Challenges of Today and Tomorrow, which was attended by over 400 researchers and engineers from Israel's High-Tech Industry and Israeli Universities.

All research supported by the CMP Knowledge Center, as well as the software and tools we develop, is publicly available to the research community at-large. The research papers can be obtained from the MATRICS Publications page.

Software Tools

All software tools and benchmarks developed by the group are offered for public use. For more information please follow the links below, or visit the Software page on the MATRICS Webpage.

Infrastructures

The knowledge center provides a unique multi-processor hardware (a tightly coupled cluster server) for running CMP-related experiments. The Knowledge Center maintains two 32-core (8X4) NUMA-based HP servers. More information about the system may be found in the HP site: General Overview, Short Specification, Detailed Specification.

The Simics simulation toolkit is installed on the machines, allowing full-system simulations of CMP systems. The servers may be accessed from outside the Technion using SSH.

The infrastructure supports a broad range of CMP-related research projects. We are always happy to expand this set of projects. The infrastructure may be used, based on availability, for CMP-related research by Israeli Academia, at no cost. Use of the infrastructure is also open to CMP-related R&D in Israeli industries, based on availability, at cost price. We are currently offering two free months of usage for CMP-related R&D to Israeli companies.

Researchers interested in using the infrastructure, please send a one-page project proposal to the Knowledge Center Manager, Idit Keidar.

Supported Research

Our vision of future nanoscale integrated systems involves many processors and shared memories, interconnected by on-chip packet-switched networks. We believe it is important to tackle these challenges by an interdisciplinary team of researchers, with diverse expertise in areas such as circuits, microarchitecture, VLSI, networking and concurrent programming.

The knowledge center supports interdisciplinary research of a team of the following Principal Investigators at the Technion:

The group addresses several aspects of such systems, including:

Background and Rationale

Microcomputers are currently undergoing a paradigm shift. Previously, computer systems' speed and performance improved annually via micro-architecture improvements, which performed speculative computing to exploit instruction level parallelism, as well as by reducing circuit sizes and increasing processor frequencies. However, it is apparent nowadays that this trend cannot continue, due to the enormous power requirements of chips that operate at a high frequency. In fact, the main consideration in computer architecture design today is power efficiency per performance. Power considerations are ubiquitous: they are essential for mobile computers, due to difficulties in heat dissipation and battery life optimization, as well as for servers in data centers, where air conditioning costs are dominant. At the same time, the opportunities for exploiting instruction level parallelism have been exhausted, and the high power per performance cost of speculative execution is no longer adequate for today's design considerations.

In order to conserve energy while improving performance, a conceptual change is due. The diminishing size of CMOS technology allows for placing multiple processor cores on a single chip. The trend in computer architecture is therefore shifting from production of faster uni-processors, as was done until recently, to architectures based on multiple cores on the same chip. Thus, instead of a single energy inefficient core (processor), the chip will include many slower, and hence more energy-efficient, cores. Computer manufacturers are already producing systems with 2, 4, and 8 processor cores. In the future, such systems are projected to increase to incorporate dozens of cores. This approach is called Chip MultiProcessor (CMP).

The shift to CMP mandates a shift to exploiting thread-level parallelism, instead of instruction level parallelism as in traditional systems. New research is needed in order to design appropriate software structures for highly parallel mutli-threading in order to address the needs of software developers for CMP architectures. Communication and synchronization among the parallel computing elements will become a major bottleneck in such systems. It is expected that such future software models will be based on shared memory rather than on direct core-to-core message passing. In this context, the structure, layout, and functionality of the on-chip cache hierarchy will be of utmost importance. It is expected that the on-chip caches will be distributed, and will have non-uniform access times. That is, different processors will incur different access times to different memory units, based on physical distance on the chip and other architectural considerations.

The inevitable shift to CMP architectures raises a multitude of research problems and challenges, whose solution is of critical importance to the advancement of this technology. These problems arise in several different tiers, including:

Typically, each of these tiers (research topics) is pursued in a separate scientific community, with expertise in its respective area, publishing in its own conferences and journals. Researchers within each community make standard (fixed) assumptions about the operation modes and cost models of other tiers.

Nevertheless, we argue that a dramatic paradigm shift such as the switch to CMP mandates the removal of the traditional barriers between communities, since the standard assumptions reflect operations modes of the past, and are inadequate for the new reality. Scientific progress and technological development in this area must rely on multi-disciplinary research, traversing all the relevant tiers, and creating new interactions among them.