Exploration of Heterogeneous FPGA Architectures

Mesh-based heterogeneous FPGAs are commonly used in industry and academia due to their area, speed, and power benefits over their homogeneous counterparts. These FPGAs contain a mixture of logic blocks and hard blocks where hard blocks are arranged in fixed columns as they offer an easy and compact layout. However, the placement of hard-blocks in fixed columns can potentially lead to underutilization of logic and routing resources and this problem is further aggravated with increase in the types of hard-blocks. This work explores and compares different floor-planning techniques of mesh-based FPGA to determine their effect on the area, performance, and power of the architecture. A tree-based architecture is also presented; unlike mesh-based architecture, the floor-planning of heterogeneous tree-based architecture does not affect its routing requirements due to its hierarchical structure. Both mesh and tree-based architectures are evaluated for three sets of benchmark circuits. Experimental results show that a more flexible floor-planning in mesh-based FPGA gives better results as compared to the column-based floor-planning. Also it is shown that compared to different floor-plannings of mesh-based FPGA, tree-based architecture gives better area, performance, and power results

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

Background Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide.Methods A multimethods analysis was performed as part of the GlobalSurg 3 study-a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital.Findings Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3.85 [95% CI 2.58-5.75]; p<0.0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63.0% vs 82.7%; OR 0.35 [0.23-0.53]; p<0.0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer.Interpretation Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised

Design and exploration of application-specific mesh-based FPGA architectures

La production en faible volume des produits à base de FPGA est très efficace et économique, car ils sont faciles à concevoir et à programmer dans le plus court délai. Les ressources reconfigurables génériques dans FPGA peuvent être programmées pour exécuter une vaste gamme d'applications en temps mutuels exclusifs. Toutefois, la flexibilité des FPGAs les rend beaucoup plus larges, plus lents et consommants plus de courant que leurs homologues ASICs. Par conséquent, les FPGAs sont inadaptés aux applications nécessitant un volume élevé de production, une haute performance ou une faible consommation de puissance. Le thème principal de ce travail consiste à réduire la surface du FPGA en introduisant des blocs durs hétérogènes (comme des multiplicateurs, additionneurs, etc.) dans les FPGAs, et en concevant des FPGAs à application spécifique. Ce travail présente un nouvel environnement pour l'exploration des architectures FPGA hétérogènes à base de structures matricielles. Des techniques automatiques pour la génération de layout du FPGA sont employées pour diminuer le coût de développement et de réalisation (NRE: Non-Recurring Engineering) et le temps de mise sur le marché des architectures FPGA hétérogènes à applications spécifiques. L'environnement d'exploration pour FPGA hétérogène est amélioré pour explorer des FPGAs à applications spécifiques, appelé ici comme un FPGA Inflexible à application spécifique (ASIF). L'idée principale est d'effectuer le prototypage, les tests et même d'envoyer le shipment initial d'une conception de circuit sur un FPGA. Plus tard, il peut être migré vers un ASIF pour une production à volume élevé.PARIS-BIUSJ-Mathématiques rech (751052111) / SudocSudocFranceF

An Improved Diffusion Based Placement Algorithm for Reducing Interconnect Demand in Congested Regions of FPGAs

An FPGA has a finite routing capacity due to which a fair number of highly dense circuits fail to map on slightly underresourced architecture. The high-interconnect demand in the congested regions is not met by the available resources as a result of which the circuit becomes unroutable for that particular architecture. In this paper, we present a new placement approach which is based on a natural process called diffusion. Our placer attempts to minimize the routing congestion by evenly disseminating the interconnect demand across an FPGA chip. For the 20 MCNC benchmark circuits, our algorithm reduced the channel width for 15 circuits. The results showed on average ~33% reduction in standard deviation of interconnect usage at an expense of an average ~13% penalty on critical path delay. Maximum channel width gain of ~33% was also observed

Application-Specific Mesh-based Heterogeneous FPGA Architectures

International audienceThis book concerns the broad domain of reconfigurable architectures and more specifically FPGAs. Different issues that are the centre of this book are very essential and are intended to overcome the current limitations of FPGAs, which are experiencing extremely rapid and sustained development for several years. In fact, FPGAs offer a particularly remarkable flexibility but suffer from a level of performance that can be disadvantageous for some applications in terms of surface, speed or energy. This work presents several significant and original contributions in order to remove these limitations by focusing especially on the surface metric. This book aims at exploring heterogeneous FPGA architectures dedicated to a given set of application circuits. Beyond architecture exploration, this work also presents automatic FPGA "layout" generation flow, and a new component called as an ASIF "Application Specific Inflexible FPGA", which significantly reduces silicon footprint by customizing the architecture for a given set of applications circuits. The importance and originality of the contributions made in this work revolve around this new concept of application specific reconfigurable circuits, mainly the development of an entire design environment including: generation tools, floor-planning, placement and routing adapted to the case of heterogeneous blocks. Careful analysis of results and the validation of proposed techniques have also been observed. The monograph of this book is based on Husain’s doctoral thesis. It was a great pleasure for me to supervise his thesis. This book will be of special interest for students and researches in the domain of FPGA architectures in general, and application-specific FPGA architectures, heterogeneous FPGA architectures, and their automatic hardware generation in particular

Enhanced Methodology and Tools for Exploring Domain-Specific Coarse-grained FPGAs

International audienceThis paper presents a new environment for the exploration of domain-specific coarse-grained FPGAs. An architecture description mechanism is used to define a coarse-grained architecture. A software flow is used to map a netlist on the defined architecture. The software flow not only maps the instances of a target netlist on their respective blocks in the architecture, but also refines the position of the blocks on the architecture. This environment can also be used to define and optimize a domain-specific architecture for a set of netlists to be mapped on it at mutually exclusive times. A set of DSP test-benches are used to show the effectiveness of various techniques used in this work

Application Specific FPGA Using Heterogeneous Logic Blocks

International audienceAn Application Specific Inflexible FPGA (ASIF) [12] is an FPGA with reduced flexibility that can implement a set of application circuits which will operate at different times. Application circuits are efficiently placed and routed on an FPGA in such a way that total routing switches used in the FPGA architecture are minimized. Later all unused routing resources are removed from the FPGA to generate an ASIF. An ASIF which is reduced from a heterogeneous FPGA (i.e. containing hard-blocks such as Multipliers, Adders and RAMS etc) is called as a Heterogeneous-ASIF. This work shows that a standard-cell based Heterogeneous-ASIF using Multipliers, Adders and Look-Up-Tables for a set of 10 opencores application circuits is 85% smaller in area than a single driver FPGA using the same blocks, and only 24% larger than the sum of areas of their standard-cell based ASIC version. If the Look-Up-Tables are replaced with a set of repeatedly used hard logic gates (such as AND gate, OR gate, flip-flops etc), the ASIF becomes 89% smaller than the Look-Up-Table based FPGA and 3% smaller than the sum of ASICs. The area gap between ASIF and sum of ASICs can be further reduced if repeatedly used groups of standard-cell logic gates in an ASIF are designed in full-custom. One of the major advantages of an ASIF is that just like an FPGA, an ASIF can also be reprogrammed to execute new or modified circuits, but at a very limited scale. A new CAD flow is presented to map application circuits on an ASIF

Heterogeneous-ASIF: An Application Specific Inflexible FPGA using Heterogeneous logic blocks

International audienceAn Application Specific Inflexible FPGA (ASIF) is an FPGA with reduced flexibility that can implement a set of application circuits which will operate at different times. Application circuits are initially placed and routed on an FPGA in such a way that the total routing switches used in the FPGA architecture are minimized. Later all unused routing resources are removed from the FPGA to generate an ASIF. An ASIF which is reduced from a heterogeneous FPGA (i.e. containing hard-blocks such as Multipliers, Adders and RAMS etc) is called as a Heterogeneous-ASIF. This work shows that a standard-cell based Heterogeneous-ASIF using Multipliers, Adders and Look-Up-Tables for a set of 10 opencores application circuits is 85% smaller in area than a single driver FPGA using the same type of blocks, and only 24% larger than the sum of areas of their standard-cell based ASIC version. If the Look-Up-Tables are replaced with a set of repeatedly used hard logic gates (such as AND gate, OR gate, FLIP-FLOPS etc), the ASIF becomes 89% smaller than the FPGA and 3% smaller than the sum of ASICs. The area gap between ASIF and sum of ASICs can be further reduced if repeatedly used groups of standard-cell logic gates in an ASIF are designed in full-custom. One of the major advantages of an ASIF is that just like an FPGA, an ASIF can also be reprogrammed to execute new or modified circuits, but at a very limited scale. A new CAD flow is presented to map application circuits on an ASIF

ASIF: Application Specific Inflexible FPGA

International audienceAn application specific inflexible FPGA (ASIF) is an FPGA with reduced flexibility that can implement a set of application circuits which will operate at mutually exclusive times. These circuits are efficiently placed and routed on an FPGA to minimize the total routing switches required by the architecture. Later all the unused routing switches are removed from the FPGA to generate an ASIF. An ASIF for a set of 17 MCNC benchmark circuits is found to be 5.43 times (81.5%) smaller than a mesh-based unidirectional FPGA required to map any of these circuits

Generic Techniques and CAD tools for automated generation of FPGA Layout

International audienceThis paper presents an automated method of generating an FPGA layout. The main purpose of developing a generator is to reduce the overall FPGA design time with limited area penalty. This generator works in two phases. In the first phase, it generates a partial layout using generic parameterized algorithms. The partial layout is generated to obtain a fast bitstream configuration mechanism, an efficient power routing and a balanced clock distribution network. In the second phase, the generator completes the remaining layout using automatic placer and router. This two-phase technique allows better maneuvering of the layout according to initial constraints. The proposed method is validated by generating the layout of an island-style FPGA which includes hardware support for the mitigation of Single Event Upsets (SEU). The FPGA layout is generated using a symbolic standard cell library which allows easy migration to any layout technology. This layout is successfully migrated to 130 nm technology