A Caltech Library Service

Packet Switched vs. Time Multiplexed FPGA Overlay Networks

Kapre, Nachiket and Mehta, Nikil and deLorimier, Michael and Rubin, Raphael and Barnor, Henry and Wilson, Michael J. and Wrighton, Michael and DeHon, André (2006) Packet Switched vs. Time Multiplexed FPGA Overlay Networks. In: FCCM 2006: 14th Annual IEEE Symposium on Field-Programmable Custom Computing Machines. Annual IEEE Symposium on Field-Programmable Custom Computing Machines . IEEE , Los Alamitos, CA, pp. 205-216. ISBN 0-7695-2661-6.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


Dedicated, spatially configured FPGA interconnect is efficient for applications that require high throughput connections between processing elements (PEs) but with a limited degree of PE interconnectivity (e.g. wiring up gates and datapaths). Applications which virtualize PEs may require a large number of distinct PE-to-PE connections (e.g. using one PE to simulate 100s of operators, each requiring input data from thousands of other operators), but with each connection having low throughput compared with the PE’s operating cycle time. In these highly interconnected conditions, dedicating spatial interconnect resources for all possible connections is costly and inefficient. Alternatively, we can time share physical network resources by virtualizing interconnect links, either by statically scheduling the sharing of resources prior to runtime or by dynamically negotiating resources at runtime. We explore the tradeoffs (e.g. area, route latency, route quality) between time-multiplexed and packet-switched networks overlayed on top of commodity FPGAs. We demonstrate modular and scalable networks which operate on a Xilinx XC2V6000-4 at 166MHz. For our applications, time-multiplexed, offline scheduling offers up to a 63% performance increase over online, packet-switched scheduling for equivalent topologies. When applying designs to equivalent area, packet-switching is up to 2× faster for small area designs while time-multiplexing is up to 5× faster for larger area designs. When limited to the capacity of a XC2V6000, if all communication is known, time-multiplexed routing outperforms packet-switching; however when the active set of links drops below 40% of the potential links, packet-switched routing can outperform time-multiplexing.

Item Type:Book Section
Related URLs:
Additional Information:© 2006 IEEE. Issue Date: 24-26 April 2006, Date of Current Version: 11 December 2006. This work was supported in part by DARPA under grant FA8750-05-C-0011, the NSF CAREER program under grant CCR-0133102, and the Microelectronics Advanced Research Consortium (MARCO) as part of the efforts of the Gigascale Systems Research Center (GSRC).
Funding AgencyGrant Number
Defense Advanced Research Projects Agency (DARPA)FA8750-05-C-0011
Microelectronics Advanced Research Consortium (MARCO)UNSPECIFIED
Gigascale Systems Research Center (GSRC)UNSPECIFIED
Other Numbering System:
Other Numbering System NameOther Numbering System ID
INSPEC Accession Number9274756
Series Name:Annual IEEE Symposium on Field-Programmable Custom Computing Machines
Record Number:CaltechAUTHORS:20110225-090013910
Persistent URL:
Official Citation:Kapre, N.; Mehta, N.; deLorimier, M.; Rubin, R.; Barnor, H.; Wilson, M.J.; Wrighton, M.; DeHon, A.; , "Packet Switched vs. Time Multiplexed FPGA Overlay Networks," Field-Programmable Custom Computing Machines, 2006. FCCM '06. 14th Annual IEEE Symposium on , vol., no., pp.205-216, 24-26 April 2006 doi: 10.1109/FCCM.2006.55 URL:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:22509
Deposited By: Benjamin Perez
Deposited On:25 Feb 2011 18:04
Last Modified:03 Oct 2019 02:38

Repository Staff Only: item control page