14181871
Performance-driven event-based synchronization for multi-FPGA simulation accelerator with event time-multiplexing bus
Simulation is the most viable solution for the functional verification of system-on-chip (SoC). The acceleration of simulation with multi-field programmable gate array (multi-FPGA) emulator is a promising method to comply with the increasing complexity and large gate capacity of SoC. Time multiplexing of interconnection wires is the inevitable solution to solve the pin limitation problem that limits the gate utilization of FPGAs and speed of multi-FPGA simulation accelerators. The most time-consuming factor of multi-FPGA simulation acceleration is the synchronization time between a software simulator and a multi-FPGA system and the inter-FPGA synchronization time. This paper proposes a performance-driven signal synchronization mechanism for a simulation accelerator with multiple FPGAs using time-multiplexed interconnection. The event-based signal synchronization optimizes the synchronization time between a software simulator and the multi-FPGA system as well as the synchronization time among FPGAs. The synchronization time among FPGAs is optimized by circuit partitioning considering the signal probability, net dependency reduction, and efficient net clustering to reduce addressing overhead. The synchronization time between the software simulator and the multi-FPGA system is also optimized by exploiting the event probability of primary nets. Experiments show that the synchronization time is reduced to 6.2-9.8% of traditional mechanisms.
5951770
MetaCore: an application specific DSP development system
This paper describes the MetaCore system which is an ASIP (Application-Specific Instruction set Processor) development system targeted for DSP applications. The goal of MetaCore system is to offer an efficient design methodology meeting specifications given as a combination of performance, cost and design turnaround time.
MetaCore system consists of two major design stages: design exploration and design generation. In the design exploration stage, MetaCore system accepts a set of benchmark programs and a formal specification of ISA (Instruction Set Architecture), and estimates the hardware cost and performance for each hardware configuration being explored. Once a hardware configuration is chosen, the system helps generate a VLSI processor design in the form of HDL along with the application program development tools such as C compiler, assembler and instruction set simulator.
14599334
Communication-efficient hardware acceleration for fast functional simulation
This paper presents new technology that accelerates system verification. Traditional methods for verifying functional designs are based on logic simulation, which becomes more time-consuming as design complexity increases. To accelerate functional simulation, hardware acceleration is used to offload calculation-intensive tasks from the software simulator. Hardware accelerated simulation dramatically reduces the simulation time. However, the communication overhead between the software simulator and hardware accelerator is becoming a new critical bottleneck. We reduce the communication overhead by exploiting burst data transfer and parallelism, which are obtained by splitting testbench and moving a part of testbench into hardware accelerator. Our experiments demonstrated that the proposed method reduces the communication overhead by a factor of about 40 compared to conventional hardware accelerated simulation while maintaining the cycle accuracy and compatibility with the original testbench.
15346879
A 3-D FPGA wire resource prediction model validated using a 3-D placement and routing tool
The interconnection architecture of FPGAs such as switches dominates performance of FPGAs. Three-dimensional integration of FPGAs overcomes interconnect limitations by allowing instances to be located and signals to be routed in 3-D space. Wire resource prediction is important for fast and accurate interconnection planning in 3-D FPGA. In this paper, we extend the existing analytic model shown in [13] with a new parameter for our 3-D FPGA which has cluster-based logic blocks. The proposed wire resource prediction model is applied to our 3-D FPGA using a Xilinx Virtex2 slice [18] and our 3-D routing architecture. We validate the effectiveness of the extended model by comparing the required number of channel wires predicted by the extended analytic equation with that of the placed and routed results using 3-D placement and routing algorithm designed for our 3-D FPGA for a number of benchmark circuits. The extended 3-D wire resource prediction model predicts the required channel capacity with an average of 11.1% error for 17 large circuits from LGSynth93 and ISPD2001 Verilog benchmarks.
1823005
Functional coverage metric generation from temporal event relation graph
Functional coverage is a technique which can be used for checking the completeness of test vectors. In this paper, automatic generation of temporal events for functional coverage is proposed. The TERG (Temporal Event Relation Graph) is the graph where the nodes represent basic temporal property and the edges represent the time-shift value between two properties. Hierarchical temporal events are generated by traversing TERG such that invalid or irrelevant properties are eliminated. Concurrent edge groups in TERG make it possible to generate more comprehensive temporal properties.
17804982
Signal Scheduling Driven Circuit Partitioning for Multiple FPGAs with Time-multiplexed Interconnection
FPGA-based logic emulator with large gate capacity generally comprises a large number of FPGAs. However, gate utilization of FPGAs and speed of emulation are limited by the number of signal pins among FPGAs and the interconnection architecture of the logic emulator. The time-multiplexing of interconnection wires is required for multi-FPGA system incorporating several stateof-the-art FPGAs. This paper proposes a circuit partitioning algorithm called SCATOMi(SCheduling driven Algorithm for TOMi) for multi-FPGA system incorporating four to eight FPGAs where FPGAs are interconnected through TOMi(Time-multiplexed, Off-chip, Multicasting interconnection). SCATOMi improves the performance of TOMi architecture by limiting the number of inter-FPGA signal transfers on the critical path and considering the scheduling of inter-FPGA signal transfers. The performance of the partitioning result of SCATOMi is 5.5 times faster than traditional partitioning algorithms. Experiments on architecture comparison show that, by adopting the proposed TOMi interconnection architecture along with SCATOMi, the pin count is reduced to 15.2%-81.3% while the critical path delay is reduced to 46.1%-67.6% compared to traditional architectures including mesh, crossbar and VirtualWire architecture.
42278030
Hybrid knowledge-based architecture for building an intelligent nondestructive signal inspection system
The paper deals with the methods of implementing an intelligent inspection system for monitoring the health of any device or material using a nondestructive signal. A hybrid knowledge representation and processing architecture is proposed as a solution to problems encountered in the processes of the nondestructive inspection. In the proposed system, to modularize knowledge elicitation and to make knowledge processing reliable, the task of inspection is delegated to two subsystems each of which has a proper knowledge processing scheme to match the properties of its own task. The front-end subsystem which detects the signal patterns (events) for any harmful flaw is built by integrating a fuzzified syntactic pattern recognition concept and a neural network concept. The back-end subsystem which evaluates the characteristics of the events is based upon object-oriented rule base system concepts. The methods of integrating the approaches in the proposed architecture are also proposed in the paper. The proposed architecture is verified by developing and evaluating a prototype which automatically interprets eddy current Lissajous signals to inspect the state of tubes used in nuclear power plants.
18707877
An efficient debugging method for message-based parallel programs using static analysis information
Guaranteeing reproducibility and minimizing probe effects are major issues in the parallel program debugging. The paper suggests a new debugging method, called the Detect and Reproduce method, for message-based parallel programs. The proposed method is designed to guarantee the reproducible behaviors of a target program and to alleviate probe effects by reducing both the number of the probes to be inserted into a program and the amount of information gathered by those probes. The proposed method achieves such effects by employing a static analysis technique to detect nondeterminacy. By detecting nondeterminacy before running the program, only a small number of probes are required to assure reproducibility. To analyze message-based programs statically, an MHB (minimal happened before) model is designed to catch the synchronization structures and algorithms have been developed to locate nondeterminacy based on the MHB model. Utilizing the analysis results, probes are inserted only into the places where nondeterminacy is likely to take place.
16141068
Improving cohesion metrics for classes by considering dependent instance variables
The existing cohesion metrics for classes do not consider the characteristics of dependent instance variables that are commonly used in a class and, thus, do not properly reflect the cohesiveness of the class. This paper presents an approach for improving the cohesion metrics by considering the characteristics of the dependent instance variables in an object-oriented program.
18311049
Testing of concurrent programs after specification changes
This paper describes a specification-based regression testing technique that can be applied for revalidating concurrent programs after specification changes. This kind of regression testing technique requires sequencing constraints which specify the precedence relations among synchronization events. In our method, the sequencing constraints are extracted automatically from Message Sequence Charts (MSCs) that are considered to be partial and nondeterministic specifications. We show how to identify the sequencing constraints affected by the modifications of a specification rather than creating new sequencing constraints from scratch to reduce the cost of regression testing. We also describe how to determine whether the affected sequencing constraints are satisfied by the program being tested.
5100963
Scalable Modeling and Performance Evaluation of Wireless Sensor Networks
A notable features of many proposed Wireless Sensor Networks (WSNs) deployments is their scale: hundreds to thousands of nodes linked together. In such systems, modeling the state of the entire system as a cross-product of the states of individual nodes results in the well-known state explosion problem. Instead, we represent the system state by the probability distribution on the state of each node. In other words, the system state represents the probability that a randomly picked node is in a certain state. Although such statistical abstraction of the global state loses some information, it is nevertheless useful in determining many performance metrics of systems that exhibit Markov behavior. We have previously developed a method for specifying the performance metrics of such systems in a probabilistic temporal logic called iLTL and for evaluating the behavior through a novel method for model checking iLTL properties. In this paper, we describe a method for estimating the probabilities in a Discrete Time Markov Chain (DTMC) model of a large-scale system. We also provide a statistical test so that we can reject estimated DTMCs if the actual system does not have Markov behavior. We describe results of experiments applying our method toWSNs in an experimental test-bed, as well as using simulations. The results of our experiments suggest that our model estimation and model checking method provides a systematic, precise and easy way of evaluating performance metrics of some large-scale WSNs.