Designing Multisocket Systems with Silicon Photonics
Technical Report Identifier: EECS-2009-189
December 21, 2009
Abstract: To fuel an increasing need for parallel performance, system designers have resulted to using multiple sockets to provide more hardware parallelism. These multisocket systems have limited off-chip bandwidth due to their electrical interconnect which is both power and pin limited. Current systems often use of a Non-Uniform Memory Architecture (NUMA) to get the most system memory bandwidth from limited off-chip bandwidth. A NUMA system complicates the work of a performance programmer or operating system, because they must maintain data locality to maintain performance.
Silicon photonics is an emerging technology that promises great off-chip bandwidth density and energy efficiency when compared to electrical signaling. With this abundance of bandwidth, it will be possible to build a relatively flat, high bandwidth memory interconnect. Because this interconnect has uniform bandwidth, NUMA optimizations will be unnecessary, which increases performance programmer productivity.
If the penalties to making a multi-socket system are negated by the use of silicon photonics, there is less incentive to integrate, and economic incentives to disintegrate. In this thesis, we present this scalable and coherent multi-socket design along with discussing the tradeoffs facing an architect when incorporating silicon photonics technology.