Current discrete event simulator requires heavy simulation overhead to switch between different components to simulate them in strictly chronological order. Therefore, timed simulation is significantly slower than un-timed simulation. By simply adding delays in the components and communication channels, our timed MPEG-2 decoder simulates more than 14 times slower than an un-timed simulation. In this paper, we propose a partial order method to speed up timed simulation by relaxing the order that the components are simulated. With partial order method, a component is not required to schedule a channel access if both behavioral and timing results of the access are known. The simulation switches less frequently hence the simulation overhead reduces. We show that partial order method can be used in complex system-level simulation such as MPSoC implementations of the MPEG-2 decoder. In our experiments, partial order method provides more than 10 times speedups over regular discrete event simulation for timed simulation.

Performance simulation of software for multiprocessor system-on-a-chips (MPSoC) suffers from poor tool support. Cycle accurate simulation at Instruction Set Simulation level is too slow and inefficient for any design of realistic size. Behavioral simulation, though useful for functional analysis at high level, does not provide any performance information that is crucial for design and analysis of MPSoC implementations. As a consequence, designers are often reduced to manually annotate performance information onto behavioral models, which contributes further to inefficiency and inaccuracy. In this paper, we use structural performance models to provide fast and accurate simulation of software for MPSoC.We generate structural models automatically using GCC with accurate performance annotation while considering optimizations for instruction selection, branch prediction, and pipeline interlock. Our structural models are able to simulate at several orders of magnitude faster than ISS and provide less than 1% error on performance estimation. These models allow realistic MPSoC design space explorations based on performance characteristics with simulation speed comparable to behavioral simulation. We validate our simulation models with several benchmarks and demonstrate our approach with a design case study of an MPEG-2 decoder.

Design of Multiprocessor System-on-a-Chips requires efficient and accurate simulation of every component. Since thememory subsystemaccounts for up to 50%of the performance and energy expenditures, it has to be considered in systemlevel design space exploration. In this paper, we present a novel technique to simulate memory accesses in software TLM/T models. We use a compiler to automatically expose all memory accesses in software and annotate them onto efficient TLM/T models. A reverse address map provides target memory addresses for accurate cache and memory simulation. Simulating at more than 10 MHz, our models allow realistic architectural design space explorations on memory subsystems. We demonstrate our approach with a design exploration case study of an industrial-strength MPEG-2 decoder.

With the increasing complexity and heterogeneity of embedded electronic systems, a unified design methodology at higher levels of abstraction becomes a necessity. Meanwhile, it is also important to incorporate the current design practice emphasizing IP reuse at various abstraction levels. However, the abstraction gap prohibits easy communication and synchronization in IP integration and co-simulation. In this paper, we present a communication infrastructure for an integrated design framework that enables co-design and co-simulation of heterogeneous design components specified at different abstraction levels and in different languages. The core of the approach is to abstract different communication interfaces or protocols to a common high level communication semantics. Designers only need to specify the interfaces of the design components using extended regular expressions; communication adapters can then be automatically generated for the co-simulation or other co-design and co-verification purposes.

In the design of highly complex, heterogeneous, and concurrent systems, deadlock detection and resolution remains an important issue. In this paper, we systematically analyze the synchronization dependencies in concurrent systems modeled in the Metropolis design environment, where system functions, high level architectures and function-architecture mappings can be modeled and simulated. We propose a data structure called the dynamic synchronization dependency graph, which captures the runtime (blocking) dependencies. A loop-detection algorithm is then used to detect deadlocks and help designers quickly isolate and identify modeling errors that cause the deadlock problems. We demonstrate our approach through a real world design example, which is a complex functional model for video processing and a high level model of function-architecture mapping.

The advent of sensor networks presents untapped opportunities for synthesis. We examine the problem of synthesis of behavioral specifications into networks of programmable sensor blocks. The particular behavioral specification we consider is an intuitive user-created network diagram of sensor blocks, each block having a pre-defined combinational or sequential behavior. We synthesize this specification to a new network that utilizes a minimum number of programmable blocks in place of the predefined blocks, thus reducing network size and hence network cost and power. We focus on the main task of this synthesis problem, namely partitioning pre-defined blocks onto a minimum number of programmable blocks, introducing the efficient but effective PareDown decomposition algorithm for the task. We describe the synthesis and simulation tools we developed. We provide results showing excellent network size reductions through such synthesis and significant speedups of our algorithm over exhaustive search while obtaining near-optimal results for 15 real network designs as well as nearly 10000 randomly generated designs.

With the scaling of technology and higher requirements on performance and functionality, power dissipation is becoming one of the major design considerations in the development of network processors. We use an assertion-based methodology for system-level power/performance analysis to study two dynamic voltage scaling (DVS) techniques, traffic-based DVS and execution-based DVS, in a network processor model. Using the automatically generated distribution analyzers, we analyze the power and performance distributions and study their trade-offs for the two DVS policies with different parameter settings, such as threshold values and window sizes. We discuss the optimal configurations of the two DVS policies under different design requirements. By a set of experiments, we show that the assertion-based trace analysis methodology is an efficient tool that can help a designer easily compare and study optimal architectural configurations in a large design space.

We describe the development of a set of embedded system building blocks, known as eBlocks. An eBlock network can be viewed as a basic form of sensor network that can be developed by non-programming engineers, scientists, and others. Each eBlock has a defined function, either one of a few predefined combinational or sequential functions, a custom-programmed function defined by an automated tool, or by user with programming skills. A user creates an application simply by connecting blocks, and possibly performing simple configuration via dials and switches. We have built over 100 physical eBlock prototypes, and tested their usability with over 100 non-programming users to date. We will describe the architecture of the blocks, including design tradeoffs we considered and the benefit of an exploration tool that we developed to help optimize the power and performance of the design. We have also built a graphical eBlock simulator that users can utilize to quickly build and test systems before deployment, and that we have used in experiments with over 300 non-programming users to help us define intuitive block functions and interfaces. We will describe the simulator architecture, as well as a tool that automatically converts a user's eBlock network into a much smaller network of programmable blocks with accompanying automatically generated programs.

System level modeling with executable languages such as C/C++ has been crucial in the development of large electronic systems from general processors to application specific designs. To make sure that the executable models behave as they should, the designers often have to "eye-ball" the simulation traces and at best, apply simple "assert" statements or write simple trace checkers in some scripting languages. The problem is the lack of a concise and formal method to specify and check desired properties, whether they be functional or performance in nature. In this paper, we apply assertion checking methodology to the system design of network processors. Functional and performance assertions, based on linear temporal logic and logic of constraints, are written during the design process. Trace checkers and simulation monitors are automatically generated to validate particular simulation runs or to analyze their performance characteristics. Several categories of assertions are checked throughout the design process, such as equivalence, functionality, transaction, and performance. We demonstrate that the assertion-based methodology is very useful for both system level verification and design exploration.

In the era of billion-transistor design, it is critical to establish effective verification methodologies from the system level, all the way down to the implementations. In this paper, we introduce logic of constraints (LOC), a logic that is particularly suited to express quantitative performance constraints as well as functional constraints. We analyze the expressiveness of LOC and show that it is important and different from linear temporal logic, upon which traditional hardware assertion languages (e.g., PSL and OpenVera) are based. We propose an automatic simulation trace checking/runtime monitoring methodology that can be used to verify system designs very efficiently. Since a subset of LOC is decidable, we also discuss the formal verification approach for LOC formulas. Through several industrial case studies, we demonstrate the usefulness of the LOC formalism and the corresponding simulation and verification approach at the higher transaction level of abstraction.

Verification of system designs continues to be a major challenge today. Simulation remains the primary tool for making sure that implementations perform as they should. We present algorithms to automatically generate trace checkers from formulas written in the formal quantitative constraint language, Logic Of Constraints (LOC), to analyze the simulation traces for functional and performance constraint violations. For many interesting formulas, the checkers exhibit linear time complexity and constant memory usage. We illustrate the usefulness and efficiency of this approach with large designs and traces.

Design space exploration is the process of analyzing several functionally equivalent alternatives to determine the most suitable one. A fundamental question is whether an implementation is consistent with the high-level specification or whether two implementations are "equivalent." The synchronous assumption has made it possible to develop efficient procedures for establishing functional equivalence between different implementations in the domains of synchronous circuits and synchronous reactive systems. We extend this notion to embedded systems that do not satisfy the synchronous assumption inside their boundaries but only at the interface with the environment. Leveraging this property, we define synchronous equivalence for embedded systems that strongly resembles the concept of functional equivalence for sequential circuits. We develop efficient synchronous equivalence analysis algorithms for embedded system designs. The efficiency comes from analyzing the behavior statically on abstract representations, at a cost that some of the negative results may be false, i.e. the analysis is conservative. We develop primitives for making the representation more/less abstract, trading off complexity of the algorithms with the conservativeness of the results. We apply our analysis algorithms to an ATM switch and demonstrate that synchronous equivalence opens design exploration avenues uncharted before.

Design space exploration is the process of analyzing several functionally equivalent alternatives to determine the most suitable one. The synchronous assumption has made it possible to develop efficient procedures for establishing functional equivalence between different implementations in the domain of synchronous circuits as well as in the domain of synchronous reactive systems. We extend this notion to embedded systems that do not satisfy the synchronous assumption inside their boundaries but only at the interface with the environment Leveraging this property, we developed efficient synchronous equivalence analysis algorithms for embedded systems with loops and architectures with multiple computational units. We demonstrate our method on an ATM switch containing many interacting components.

Design exploration consists of analyzing several alternative implementations of the "same" function to determine the most desirable one. A fundamental question is whether an "implementation" is consistent with the high-level specification or whether two implementations are "equivalent". We define synchronous equivalence for embedded systems that strongly resembles the concept of functional equivalence for sequential circuits. We then present equivalence analysis algorithms that are of low polynomial complexity. We show an example of application of the algorithms to a real-life design (a shock absorber controller) and demonstrate that synchronous equivalence opens up design exploration avenues uncharted before.

Software components for embedded reactive real-time applications must satisfy tight code size and run-time constraints. Cooperating finite state machines provide convenient intermediate format for embedded system co-synthesis, between high-level specification languages and software or hardware implementations. We propose a software generation methodology that takes advantage of a restricted class of specifications and allows for tight control over the implementation cost. The methodology exploits several techniques from the domain of Boolean function optimization. We also describe how the simplified control/data-flow graph used as an intermediate representation can be used to accurately estimate the size and timing cost of the final executable code.

Both timing and functional properties are essential to characterize the correct behavior of an embedded system.Verication is in general performed either by simulation, or by bread-boarding.Given the safety requirements of such systems, a formal proof that the properties are indeed satised is highly desirable.In this paper, we present a formal veri cation methodology for embedded systems.The formal model for the behavior of the system used in POLIS is a network of Codesign Finite State Machines.This model is translated into automata, and veri ed using automatatheoretic techniques.An industrial embedded system is veri ed using the methodology.W e demonstrate that abstractions and separation of timing and functionality is crucial for the successful use of formal veri cation for this example.We also show that in POLIS abstractions and separation of timing and functionality can be done by simple syntactic modi cation of the representation of the system.

Article Free Access Share on Synthesis of software programs for embedded control application Authors: Massimiliano Chiodo Magneti Marelli, Italy Magneti Marelli, ItalyView Profile , Paolo Guisto Magneti Marelli, Italy Magneti Marelli, ItalyView Profile , Attila Jurecska Magneti Marelli, Italy Magneti Marelli, ItalyView Profile , Luciano Lavagno Dipartimento di Elettronica, Politecnico di Torino, Italy Dipartimento di Elettronica, Politecnico di Torino, ItalyView Profile , Ellen Sentovich Cadence Berkeley Labs, Berkeley, CA Cadence Berkeley Labs, Berkeley, CAView Profile , Harry Hsieh Department of EECS, Univ. of California, Berkeley, CA Department of EECS, Univ. of California, Berkeley, CAView Profile , Kei Suzuki Department of EECS, Univ. of California, Berkeley, CA Department of EECS, Univ. of California, Berkeley, CAView Profile , Alberto Sangiovanni-Vincentelli Department of EECS, Univ. of California, Berkeley, CA Department of EECS, Univ. of California, Berkeley, CAView Profile Authors Info & Claims DAC '95: Proceedings of the 32nd annual ACM/IEEE Design Automation ConferenceJanuary 1995 Pages 587–592https://doi.org/10.1145/217474.217594Published:01 January 1995Publication History 36citation320DownloadsMetricsTotal Citations36Total Downloads320Last 12 Months5Last 6 weeks1 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF