1,720,969 research outputs found
On-Chip Transparent Wire Pipelining (invited paper)
Full text linkWire pipelining has been proposed as a viable mean to break the discrepancy between decreasing gate delays and increasing wire delays in deep-submicron technologies. Far from being a straightforwardly applicable technique, this methodology requires a number of design modifications in order to insert it seamlessly in the current design flow. In this paper we briefly survey the methods presented by other researchers in the field and then we thoroughly analyze the solutions we recently proposed, ranging from system-level wire pipelining to physical design aspects
Throughput-driven floorplanning with wire pipelining
Full text linkThe size of future high-performance SoC is such that the time-of-flight of wires connecting distant pins in the layout can be much higher than the clock period. In order to keep the frequency as high as possible, the wires may be pipelined. However, the insertion of flip-flops may alter the throughput of the system due to the presence of loops in the logic netlist. In this paper, we address the problem of floorplanning a large design where long interconnects are pipelined by inserting the throughput in the cost function of a tool based on simulated annealing. The results obtained on a series of benchmarks are then validated using a simple router that breaks long interconnects by suitably placing flip-flops along the wires
A new system design methodology for wire pipelined SoC
Full text linkWire Pipelining (WP) has been proposed in order to limit the impact of increasing wire delays. In general, the added pipeline elements alters the system such that architectural changes are needed to preserve functionality. We illustrate a proposal that, while allowing the use of IP blocks without modification, takes advantage of a minimal knowledge of the IP's communication profile to dramatically increase the performances. We showed the formal equivalence between WP and original system and proved the higher performance achievable through a relevant case study
Adaptive Latency Insensitive Protocols
Full text linkLatency-insensitive design copes with excessive delays typical of global wires in current and future IC technologies. It achieves its goal via encapsulation of synchronous logic blocks in wrappers that communicate through a latency-insensitive protocol (LIP) and pipelined interconnects. Previously proposed solutions suffer from an excessive performance penalty in terms of throughput or from a lack of generality. This article presents an adaptive LIP that outperforms previous static implementations, as demonstrated by two relevant cases — a microprocessor and an MPEG encoder — whose components we made insensitive to the latencies of their interconnections through a newly developed wrapper. We also present an informal exposition of the theoretical basis of adaptive LIPs, as well as implementation detail
Floorplan assisted data rate enhancement through wire pipelining: a real assessment
No full textThe recent shift towards wire pipelining (WP) mandated by technological factors has attracted attention towards latency-controlled floorplanning, However, no systematic study has been published so far that takes into account block and logic delay limitations. The present work aims at filling the gap by showing that block delay can limit and possibly prevent any real gain WP might promise, Recurring to adaptive WP schemes, on the other hand, allows relevant gains. We built a floorplanner that optimizes for maximum data rate, taking into account various models of block delay, and compares them to the optimal results obtained when no wire pipelining is employed. Experiments with suitable floorplanning benchmarks and case studies are performed to substantiate theoretical intuitions
Issues in Implementing Latency Insensitive Protocols
Full text linkThe latency insensitive protocols (LIP), which are designed to improve the performance of systems-on-chip, were refined. The refined protocol was validated by using many proof-of-concept examples, that comprised of various combinations of feedforward and feedback topologies. All examples were successfully simulated using VHDL description of all blocks and an event-driven simulator. The results show that the protocol refinement allows precise calculations of important design parameters, like system throughput and transient length
Floorplanning for Throughput
No full textLarge Systems-on-Chip (SoC) in advanced technologies run at such high frequencies that the time-of-flight of signals connecting two distant pins in the layout can be higher than the clock period. In order to avoid performance penalties wires are pipelined using latches. However the throughput of the system may be altered due to the presence of loops in the logic netlist. In this paper we address the problem of floorplanning a large design with interconnect pipelining and inserting throughput in the cost function of the floor-planning algorithm. The throughput results obtained on a series of benchmarks are then validated using a simple router that places flipflops along the nets built with an heuristical minimum rectilinear Steiner tree
A new approach to latency insensitive design
No full textLatency Insensitive Protocols have been proposed as a viable mean to speed up large Systems-on-Chip where the limit in clock frequency is given by long global wires connecting together functional blocks. In this paper we keep the philosophy of Latency Insensitive Design and show that a drastic simplification can be done that results in even no need to implement any kind of protocol. By using a scheduling algorithm for the functional blocks activation we greatly reduce the routing resources demand of the old protocol, the area occupied by the sequential elements used to pipeline long interconnects and the complexity of the gating structure used to activate the modules
Adaptive Latency Insensitive Protocols andElastic Circuits with Early Evaluation: A Comparative Analysis
Full text linkAbstractLatency Insensitive Protocols (LIP) and Elastic Circuits (EC) solve the same problem of rendering a design tolerant to additional latencies caused by wires or computational elements. They are performance-limited by a firing semantics that enforces coherency through a lazy evaluation rule: Computation is enabled if all inputs to a block are simultaneously available. Adaptive LIP's (ALIP) and EC with early evaluation (ECEE) increase the performance by relaxing the evaluation rule: Computation is enabled as soon as the subset of inputs needed at a given time is available. Their difference in terms of implementation and behavior in selected cases justifies the need for the comparative analysis reported in this paper. Results have been obtained through simple examples, a single representative case-study already used in the context of both LIP's and EC and through extensive simulations over a suite of benchmarks
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