Developing Field-programmable Gate Array (FPGA) architectures is challenging due to the competing requirements of various application domains and changing manufacturing process technology. This is compounded by the difficulty of fairly evaluating FPGA architectural choices, which requires sophisticated high-quality Computer Aided Design (CAD) tools to target each potential architecture. This article describes version 8.0 of the open source Verilog to Routing (VTR) project, which provides such a design flow. VTR 8 expands the scope of FPGA architectures that can be modelled, allowing VTR to target and model many details of both commercial and proposed FPGA architectures. The VTR design flow also serves as a baseline for evaluating new CAD algorithms. It is therefore important, for both CAD algorithm comparisons and the validity of architectural conclusions, that VTR produce high-quality circuit implementations. VTR 8 significantly improves optimization quality (reductions of 15% minimum routable channel width, 41% wirelength, and 12% critical path delay), run-time (5.3× faster) and memory footprint (3.3× lower). Finally, we demonstrate VTR is run-time and memory footprint efficient, while producing circuit implementations of reasonable quality compared to highly-tuned architecture-specific industrial tools—showing that architecture generality, good implementation quality, and run-time efficiency are not mutually exclusive goals.

https://dl.acm.org/doi/pdf/10.1145/3388617

VTR 8: High-performance CAD and Customizable FPGA Architecture Modelling

With the end of both Dennard's scaling and Moore's law, computer users and researchers are aggressively exploring alternative forms of computing in order to continue the performance scaling that we have come to enjoy. Among the more salient and practical of the post-Moore alternatives are reconfigurable systems, with Coarse-Grained Reconfigurable Architectures (CGRAs) seemingly capable of striking a balance between performance and programmability. In this paper, we survey the landscape of CGRAs. We summarize nearly three decades of literature on the subject, with a particular focus on the premise behind the different CGRAs and how they have evolved. Next, we compile metrics of available CGRAs and analyze their performance properties in order to understand and discover knowledge gaps and opportunities for future CGRA research specialized towards High-Performance Computing (HPC). We find that there are ample opportunities for future research on CGRAs, in particular with respect to size, functionality, support for parallel programming models, and to evaluate more complex applications.

A Survey on Coarse-Grained Reconfigurable Architectures From a Performance Perspective

In this paper we describe Xilinx's Versal-Adaptive Compute Acceleration Platform (ACAP). ACAP is a hybrid compute platform that tightly integrates traditional FPGA programmable fabric, software programmable processors and software programmable accelerator engines. ACAP improves over the programmability of traditional reconfigurable platforms by introducing newer compute models in the form of software programmable accelerators and by separating out the data movement architecture from the compute architecture. The Versal architecture includes a host of new capabilities, including a chip-pervasive programmable Network-on-Chip (NoC), Imux Registers, compute shell, more advanced SSIT, adaptive deskew of global clocks, faster configuration, and other new programmable elements as well as enhancements to the CLB and interconnect. We discuss these architectural developments and highlight their key motivations and differences in relation to traditional FPGA architectures.

Xilinx Adaptive Compute Acceleration Platform: Versal TM Architecture

In this white paper we provide a vision for 6G Edge Intelligence. Moving towards 5G and beyond the future 6G networks, intelligent solutions utilizing data-driven machine learning and artificial intelligence become crucial for several real-world applications including but not limited to, more efficient manufacturing, novel personal smart device environments and experiences, urban computing and autonomous traffic settings. We present edge computing along with other 6G enablers as a key component to establish the future 2030 intelligent Internet technologies as shown in this series of 6G White Papers. 
In this white paper, we focus in the domains of edge computing infrastructure and platforms, data and edge network management, software development for edge, and real-time and distributed training of ML/AI algorithms, along with security, privacy, pricing, and end-user aspects. We discuss the key enablers and challenges and identify the key research questions for the development of the Intelligent Edge services. As a main outcome of this white paper, we envision a transition from Internet of Things to Intelligent Internet of Intelligent Things and provide a roadmap for development of 6G Intelligent Edge.

6G White Paper on Edge Intelligence

A Test Wrapper and associated Test Access Mechanism (TAM) architecture for facilitating testing of IP blocks integrated on a System on a Chip (SoC). The TAM architecture includes a Test Controller and one or more Test Wrappers that are integrated on the SoC proximate to IP blocks. Test data and commands corresponding to input from an external tester are packaged by the Test Controller and sent to one or more Test Wrappers via an interconnect fabric. The Test Wrappers interface with one or more IP test ports to provide test data, control, and/or stimulus signals to the IP blocks to facilitate circuit-level testing of the IP blocks. Test results for the circuit-level tests are returned to the Test Controller via the fabric. Test Wrappers may be configured to pass through interconnect signals, enabling functional testing of IP blocks to be facilitated via test packages and test results transmitted between the Test Controller and the IP blocks via the fabric. Test wrappers may also be configured to test multiple IP blocks comprising a test partition.

A functional fabric based test wrapper for circuit testing of ip blocks

This paper outlines the Network-on-Chip (NoC) on Xilinx's next generation Versal-architecture. It is a hardened NoC that is present in Xilinx's next-generation 7nm architecture devices. These devices include many other new hardened features that make up the Adaptable Computing Acceleration Platform (ACAP) devices. There is a trend in FPGA devices of hardening many commonly used components such as processors, memory controllers and other IO controllers. The next generation of Xilinx devices take this a step further by providing a device-global memory mapped NoC which connects these components and the fabric in an integrated fashion. The NoC unifies communication between the processor system, FPGA fabric, memory subsystem and other hardened accelerator functions. This paper gives an overview of the Versal architecture NoC. It also motivates some of the specific characteristics of the architecture. We show how hardening the NoC lets users quickly implement high performance system level interconnect.

Network-on-Chip Programmable Platform in VersalTM ACAP Architecture

Boolean Satisfiability (SAT)-based routing offers a unique advantage over conventional routing algorithms by providing an exhaustive approach to find a solution. Despite that advantage, commercial FPGA CAD tools rarely use SAT-based routers due to scalability issues. In this paper, we revisit SAT-based routing and propose two SAT formulations independent of routing architecture. We then demonstrate that SAT-based routing using either formulation dramatically outperforms conventional routing algorithms in both runtime and robustness for the clock routing of Xilinx UltraScale devices. Finally, we experimentally show that one of the proposed SAT formulations leads to a routing 18x faster and produces formulas 20x more compact than the other. This framework has been implemented into Vivado and is now currently used in production.

Boolean Satisfiability-Based Routing and Its Application to Xilinx UltraScale Clock Network

Each generation of FPGA architecture benefits from optimizations around its technology node and target usage. In this paper, we discuss some of the changes made to the CLB for Xilinx's 20nm UltraScale product family. We motivate those changes and demonstrate better results than previous CLB architectures on a variety of metrics. We show that, in demanding scenarios, logic placed in an UltraScale device requires 16% less wirelength than 7-series. Designs mapped to UltraScale devices also require fewer logic tiles. In this paper, we demonstrate the utilization benefits of the UltraScale CLB attributed to certain CLB enhancements. The enhancements described herein result in an average packing improvement of 3% for the example design suite. We also show that the UltraScale architecture handles aggressive, tighter packing more gracefully than previous generations of FPGA. These significant reductions in wirelength and CLB counts translate directly into power, performance and ease-of-use benefits.

https://dl.acm.org/doi/pdf/10.1145/2684746.2689077

Enhancements in UltraScale CLB Architecture

A computer-implemented method of converting a circuit design for a programmable logic device (PLD) to a standard cell circuit design can include unmapping a PLD circuit design to a gate level netlist (110), mapping logic gates of the netlist to functionally equivalent standard cells (120), and including the standard cells within the standard cell circuit design (125). Design constraints for the standard cell circuit design can be automatically generated (135, 140). The design constraints for the standard cell circuit design can be output (145).

Dinesh D. Gaitonde

Papers

Xilinx Adaptive Compute Acceleration Platform: Versal TM Architecture

Network-on-Chip Programmable Platform in VersalTM ACAP Architecture

Boolean Satisfiability-Based Routing and Its Application to Xilinx UltraScale Clock Network

Enhancements in UltraScale CLB Architecture

Creating a standard cell circuit design from a programmable logic device circuit design