Prototyping using multi-FPGA systems offers significant advantages over simulation and emulation based pre-silicon verification techniques. Multi-FPGA prototyping follows a complex design flow where the quality of associated tools and the architecture of interconnect topology play a very important role in the performance of final prototyped design. A well designed interconnect topology may remain underutilized because of a poor routing tool and vice versa. This makes the selection of a good routing tool and the exploration of interconnect topologies extremely important for the quality of final design. In this work, we present a detailed comparison between six inter-FPGA interconnect topologies. We present a generic routing tool and for each topology, ten large, complex benchmarks are prototyped on four FPGA boards using this tool. Experimentation reveals that fully customized interconnect topology using a hybrid combination of direct two and multi point tracks gives the best frequency results for all the FPGA boards. On average, this topology gives 26.2, 28.5, 9.5, 32.1 and 12.4% better frequency results as compared to five other interconnect topologies. We also perform routing time comparison and the topology using generic hybrid combination of direct two and multi point tracks gives the best results. On average, this topology produces \(1.8\times \), \(2\times \), \(2\times \), \(9.2\times \), and \(4.4\times \) better results as compared to five other topologies under consideration. Frequency–time tradeoff analysis along with flexibility and setup time of different topologies is also performed. It reveals that a partially customized topology with hybrid combination of direct two and multi point tracks gives the best frequency–time tradeoff for smaller FPGA boards while a partially customized topology with switch-based and multi point connections gives the best results for larger FPGA boards with reasonable flexibility and moderate setup time.

中文翻译：

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多FPGA系统之间的FPGA间互连拓扑探索

与基于仿真和仿真的硅前验证技术相比，使用多FPGA系统进行原型设计具有明显的优势。多FPGA原型设计遵循复杂的设计流程，其中相关工具的质量和互连拓扑的体系结构在最终原型设计的性能中起着非常重要的作用。由于路由工具不佳，设计良好的互连拓扑可能仍未得到充分利用，反之亦然。这使得选择一个好的布线工具和探索互连拓扑对于最终设计的质量极为重要。在这项工作中，我们给出了六个FPGA间互连拓扑之间的详细比较。我们提供了一种通用的路由工具，对于每种拓扑，使用该工具在四个FPGA板上原型制作了十个大型，复杂的基准测试。实验表明，使用直接的两点和多点轨迹的混合组合的完全定制的互连拓扑可为所有FPGA板提供最佳的频率结果。平均而言，与其他五个互连拓扑相比，此拓扑可提供26.2、28.5、9.5、32.1和12.4％的频率结果。我们还执行路由时间比较，并且使用直接两点轨迹和多点轨迹的通用混合组合来提供最佳结果。平均而言，这种拓扑会产生 我们还执行路由时间比较，并且使用直接两点和多点轨迹的通用混合组合的拓扑可提供最佳结果。平均而言，这种拓扑会产生 我们还执行路由时间比较，并且使用直接两点和多点轨迹的通用混合组合的拓扑可提供最佳结果。平均而言，这种拓扑会产生与正在考虑的其他五个拓扑相比，\（1.8 \ times \），\（2 \ times \），\（2 \ times \），\（9.2 \ times \）和\（4.4 \ times \）的结果更好。还执行了频率-时间权衡分析以及不同拓扑的灵活性和建立时间。结果表明，部分定制的拓扑结构具有直接的两点和多点轨迹的混合组合，可以为较小的FPGA板提供最佳的频率-时间权衡，而具有开关和多点连接的部分定制的拓扑结构可以为较大的FPGA板提供最佳的结果。合理的灵活性和适中的设置时间。