Pareto-set-based optimization can be found in several different areas of embedded system design. One example is task scheduling, where different task mapping and ordering choices for a target platform will lead to dif...
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ISBN:
(纸本)1581137427
Pareto-set-based optimization can be found in several different areas of embedded system design. One example is task scheduling, where different task mapping and ordering choices for a target platform will lead to different performance/cost tradeoffs. To explore this design space at run-time, a fast and effective heuristic is needed. We have modeled the problem as the well known Multiple Choice Knapsack Problem(MCKP) and have developed a fast greedy heuristic for the run-time task scheduling. To show the effectiveness of our algorithm, examples from randomly generated task graphs and realistic applications are studied. Compared to the optimal dynamic programming solver, the heuristic is more than ten times faster while the result is less than 5% away from the optimum. Moreover, due to its iterative feature, the algorithm is well suitable to be used as an on-line algorithm.
Current methods cannot synthesize real-time embedded software applications when the global deadline of a task is shorter than the total of all local deadlines along a critical path in the task. This creates unnecessar...
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ISBN:
(纸本)1581137427
Current methods cannot synthesize real-time embedded software applications when the global deadline of a task is shorter than the total of all local deadlines along a critical path in the task. This creates unnecessary modeling limitations which directly affect the types of systems synthesizable. We propose a quasi-dynamic scheduling algorithm for simultaneously guaranteeing both local and global deadlines, while satisfying all precedence constraints among sub-tasks and among tasks. Through this scheduling procedure, we are able to formally synthesize real-time embedded software from a network of Real-Time Petri Nets specification. Application examples, including a driver for the Master/Slave role switch in Bluetooth wireless communication devices, are given to illustrate the feasibility of the scheduling algorithm.
Video encoders are an important IP block in mobile multimedia systems. In this paper, we describe a low-cost low-power multi-standard (MPEG4, JPEG, and H.263) video/image encoder. The low-cost and low-power aspects ar...
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ISBN:
(纸本)1581137427
Video encoders are an important IP block in mobile multimedia systems. In this paper, we describe a low-cost low-power multi-standard (MPEG4, JPEG, and H.263) video/image encoder. The low-cost and low-power aspects are achieved by the right choice of algorithms and architectures. In the algorithm front, an embedded compression technique for reducing the size of loop memory has enabled a single-chip low-cost realization of the encoder. In the architectural front, an efficient hardware-software partitioning has contributed to the design of a low-power encoder. Further, the hardware components that accelerate the kernels of encoding are implemented as application specific instruction-set processors (ASIPs) thereby providing flexibility to address multi-standard encoding. The power and area estimates for the encoder for QCIF@15fps in 0.18mum CMOS technology are 30mW and 20mm(2) respectively including the loop memory.
NAND flash memory has become an indispensable component in mobile embedded systems because of its versatile features such as non-volatility, solid-state reliability, low cost and high density. Even though NAND flash m...
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ISBN:
(纸本)1581137427
NAND flash memory has become an indispensable component in mobile embedded systems because of its versatile features such as non-volatility, solid-state reliability, low cost and high density. Even though NAND flash memory is gaining popularity as data storage, it can be also exploited as code memory for XIP (execute-in-place). In this paper, we present a new memory architecture which incorporates NAND flash memory into an existing memory hierarchy for code execution. The usefulness of the proposed approach is demonstrated with real embedded workloads on a real prototyping board.
We present an approach to the automatic derivation of executable Process Network specifications from Weakly Dynamic Applications. We introduce the notions of Dynamic Single Assignment Code, Approximated Dependence Gra...
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ISBN:
(纸本)1581137427
We present an approach to the automatic derivation of executable Process Network specifications from Weakly Dynamic Applications. We introduce the notions of Dynamic Single Assignment Code, Approximated Dependence Graph, and Linearly Bounded Sets to model and capture weakly dynamic (data-dependent) behavior of applications at the task-level of abstraction. Process Networks are simple parallel processing models that match the emerging multi-processor architectures in the sense that the mapping of Process Network specifications of applications onto multi-processor architectures can be done in a systematic and transparent way.
systems-on-chip (SoC) continue to be very complex to design and verify, despite extensive component reuse. Although reusable components are pre-designed and pre-verified, when they are assembled in an SoC there is no ...
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ISBN:
(纸本)1581137427
systems-on-chip (SoC) continue to be very complex to design and verify, despite extensive component reuse. Although reusable components are pre-designed and pre-verified, when they are assembled in an SoC there is no guarantee that the whole system will behave as expected from a performance, cost and integration point of view. In many cases this is because of faulty early design decisions regarding the architecture, core selection, floorplanning, etc. This paper presents a system for early analysis of SoCs which helps designers make early design decisions regarding performance, area, timing and power;and allows them to quickly evaluate cross-domain effects, such as the effect that an architectural decision may have on the performance and chip area.
This paper presents a correct-by-construction synthesis method for generating operating system based device drivers from a formally specified device behavior model. Existing driver development is largely manual using ...
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ISBN:
(纸本)1581137427
This paper presents a correct-by-construction synthesis method for generating operating system based device drivers from a formally specified device behavior model. Existing driver development is largely manual using an ad-hoc design methodology. Consequently, this task is error prone and becomes a bottleneck in embedded system design methodology. Our solution to this problem starts by accurately specifying device access behavior with a formal model, viz. extended event driven finite state machines. We state easy to check soundness conditions on the model that subsequently guarantee properties such as bounded execution time and deadlock-free behavior. We design a deadlock-free resource accessing scheme for our device access model. Finally, we synthesize an operating system (OS) based event processing mechanism, which is the core of the device driver, using a disciplined methodology that assures the correctness of the resulting driver. We validate our synthesis method using two case studies: an infrared port and the USB device controller for an SA I 100 based handheld. Besides assuring a correct-by -construction driver, the size of the specification is 70% smaller than a manually written driver, which is a strong indicator of improved design productivity.
The design methodologies to address the multi-cycle on-chip communication problems were discussed. A regular distributed register (RDR) micro-architecture which offers high regularity and direct support of multi-cycle...
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The design methodologies to address the multi-cycle on-chip communication problems were discussed. A regular distributed register (RDR) micro-architecture which offers high regularity and direct support of multi-cycle communication was proposed. A set of novel architectural synthesis algorithms to efficiently synthesize behavior-level design onto the RDR architecture was developed. After comparing architectural synthesis for multi-cycle communication (MCAS) with conventional architectural synthesis flow, results achieved clock improvement of 33% and a total latency improvement of 24% on average.
We present a case study involving the implementation of a complete Wideband CDMA (WCDMA) digital receiver part of an AMR channel onto a reconfigurable core. WCDMA is one of the two major standards for the third genera...
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ISBN:
(纸本)9781581137422
We present a case study involving the implementation of a complete Wideband CDMA (WCDMA) digital receiver part of an AMR channel onto a reconfigurable core. WCDMA is one of the two major standards for the third generation (3G) cellular systems. Traditionally most of the receiver components were confined to ASIC implementation for performance, size and power consumption reasons. The MSI reconfigurable DSP core provides both a microprocessor and reconfigurable fabric as well as a variety of peripherals. The various functions of the receiver were mapped onto different core components. The complete system was tested both in simulation as well as on a hardware platform comprising a silicon implementation of the MSI DSP core.
The analysis of the amount of human resources required to complete a project is felt as a critical issue in any company of the electronics industry. In particular, early estimating the effort involved in a development...
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The analysis of the amount of human resources required to complete a project is felt as a critical issue in any company of the electronics industry. In particular, early estimating the effort involved in a development process is a key requirement for any cost-driven system-level design decision. In this paper, we present a methodology to predict the final size of a VHDL project on the basis of a high-level description, obtaining a significant indication about the development effort. The methodology is the composition of a number of specialized models, tailored to estimate the size of specific component types. Models were trained and tested on two disjoint and large sets of real VHDL projects. Quality-of-result indicators show that the methodology is both accurate and robust.
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