UBC Theses and Dissertations

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UBC Theses and Dissertations

Improving the run-time and memory scalability of FPGA CAD algorithms Chin, Scott Yin Lunn


Field-Programmable Gate Arrays (FPGAs) are pre-fabricated integrated circuits that can be configured as any digital system. Configuration is done by Computer-Aided Design (CAD) tools. The demand placed on these tools continues to grow as advances in process technology continue to allow for more complex FPGAs. Already, for large designs, compile-times of an entire work day are common and memory requirements that exceed what would be found in a typical workstation are the norm. This thesis presents three contributions toward improving FPGA CAD tool scalability. First we derive an analytical model that relates key FPGA architectural parameters to the CAD place-and-route (P&R) run-times. Validation shows that the model can accurately capture the trends in run-time when architecture parameters are changed. Next we focus on the CAD tool’s storage requirements. A significant portion of memory usage is in representing the FPGA. We propose a novel scheme for this representation that reduces memory usage by 5x-13x at the expense of a 2.26x increase in routing run-time. Storage is also required to track metrics used during routing. We propose three simple memory management schemes for this component that further reduces memory usage by 24%, 34%, and 43% while incurring a routing run-time increase of 4.5%, 6.5%, and 144% respectively. We also propose a design-adaptive scheme that reduces memory usage by 41% while increasing routing run-time by only 10.4%. Finally, we focus on the issue of long CAD run-times by investigating the design of FPGA architectures amenable to fast CAD. Specifically, we investigate the CAD run-time and area/delay trade-offs when using high-capacity logic blocks (LBs). Two LB architectures are studied: traditional and multi-level. Results show that for the considered architectures, CAD run-time can be reduced at the expense of area; speed improved. For example, CAD run-time could be reduced by 25% with an area increase of 5%. We also show that the run-time trade-offs through these architectural changes can be complementary with many previously published algorithmic speed-ups.

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Attribution-NonCommercial-NoDerivatives 4.0 International