Core-Based Testing of Multiprocessor System-on-Chips Utilizing Hierarchical Functional Buses

This paper presents an efficient method to determine minimum system-on-chip (SOC) test schedules with precedence and power constraints based on simulated annealing. The problem is solved using a partitioned testing scheme with run to completion that minimizes the number of idle test slots. The method can handle SOC test scheduling with and without power constraints in addition to precedence constraints that preserve desirable orderings among tests. We present experimental results for various SOC examples that demonstrate the effectiveness of the method. The method achieved optimal test schedules in all attempted cases in a short CPU time.

Test scheduling is a major problem in system-on-a-chip (SOC) test automation. We present an integrated framework that addresses several important test scheduling problems. We first present efficient techniques to determine optimal SOC test schedules with precedence constraints, i.e., schedules that preserve desirable orderings among tests. We then present a new algorithm that uses preemption to obtain optimal test schedules in polynomial time. Finally, we present a new method for determining optimal power-constrained schedules. Experimental results for a representative SOC show that test schedules can be obtained in reasonable CPU time for all cases.

System on a chip (SOC) based on reusable IP core has been widely used in integrated circuit (IC) design and manufacturing. However SOC efficient test is still the bottle-neck issue. Test scheduling can enhance parallel test to minimize test application time at SOC system level. We present a modified differential evolution (MDE) approach to solve the problems of test scheduling and test access mechanism (TAM) partition for system on chips. A new hybrid mutation mechanism based on the probability estimation operator is introduced in the paper for better handling test scheduling, where the first variation coefficient stays the same but the second variation coefficient changes with iterative times. The different evolutionary strategies are adopted to accelerate effectively convergence without loss in population diversity as far as possible. Different mutation operators and evolutionary strategies are combined to get optimal results. The experimental results on ITC'02 SOC benchmarks are encouraging compared with the improved quantum-inspired evolutionary (IQI), genetic algorithm (GA), the integer linear programming formulation (ILP) and heuristic approaches.

The functionality of embedded systems is ever growing. The computational power of embedded systems is growing to match this demand, with embedded multiprocessor systems becoming more common. The limitations of embedded systems are not always related to chip size but are commonly due to energy and/or power constraints. While it can be possible to embed a more powerful Multiprocessor System on Chip (MPSoC), it is not always possible to provide an energy or power supply that meets its demands within the device’s size and weight requirements. Power management through Dynamic Voltage and Frequency Scaling (DVFS) enables the device to be run at less than its maximum voltage and frequency, allowing high computational capability when necessary while conserving power at other times. Embedded systems commonly perform real-time functionality. A real-time application has an associated formal model to verify that it meets its timing requirements. This formal model is used to perform a worst-case timing analysis to ensure that the application meets its requirements. These models incorporate the worst-case timing of the application’s computation and communication. Timing changes due to power management must also be taken into account, complicating the verification process. The drive for evermore functionality has led to mixed time-criticality systems, in which multiple applications of various timing criticalities share the same (hardware) resources. This complicates the verification process further as the timing interference due to shared resource contention must be taken into account. A monolithic verification effort is therefore traditionally required after system integration and must be carried out again if any modifications are made that affect the timing of any of the applications. The problem that we aim to solve in this work is to enable real-time applications to perform independent execution and power management without violating their timing requirements or invalidating the timing verification of concurrently executing applications. To solve this problem, we contribute the Composable and Predictable Microkernel (CoMik) to composably and predictably virtualise processors. When used in combination with composable and predictable memory controllers and interconnect (as provided by the Composable and Predictable System-on-Chip (CompSOC) platform), these virtual processors cannot interfere with each other’s timing by even a single cycle. If whatever executes on the virtual processors (e.g. an Operating System (OS) or an application directly) has a real-time requirement, it can be verified independently of whatever executes on the concurrent virtual processors and other virtual resources. To enable formally analysable application execution, we contribute the Predictable Operating System (POSe) that enables dataflow applications to be executed on the (virtualised) processor. We contribute a combined application and platform dataflow graph, including an algorithm to automate this process. When annotated with worst-case timings, the combined application and system graph is then used to verify that the application meets its timing requirement. If the application’s performance is better than its requirement (e.g. when the input or platform behaviour are better than worst case), its performance can be reduced using DVFS to achieve a reduction in power consumption. We contribute an off-line convex optimisation that uses the combined application and platform dataflow model to derive static run-time operating frequency levels to achieve low power consumption. The off-line technique is able to exploit static slack in the schedule, but not dynamic run-time slack due to variations in task execution times. Before dynamic slack can be used it must be possible to observe it. For this purpose, CoMik provides independent power, energy and timing accounting per virtual processor. This enables each virtual processor to be assigned individual power and energy budgets and POSe applications to be assigned timing budgets. We contribute a description and model of how energy and power budgets can be distributed between multiple virtual processors, enabling whatever executes on the virtual processor to perform composable independent power-management without affecting the ability of other virtual processors from using their entire budget allocation. Using CoMik’s accounting infrastructure, we also demonstrate how the quality of applications can be dynamically scaled to assist meeting timing, energy or power requirements. We further contribute a distributed dynamic power management policy that enables dataflow applications that are mapped onto multiple (virtual) processors to make distributed dynamic slack observations and local power-management decisions. We demonstrate the applicability of the presented techniques on an implemented Field Programmable Gate Array (FPGA) prototype of a CompSOC hardware platform instance, using an H.263 decoder as a case-study application. We show that our techniques do not only work in theory, but that they are also implementable and implemented.

With the increase of the number of IP cores integrated in SOC, the functions of SOC ar e becoming more complexed. Test time and test cost grow rapidly, therefore it becomes bo ttleneck of SOC test. Test scheduling is one of the efficient approaches to solve the forenamed ques tion. Cross-entropy method, which is ba sed on probability density function, has been used to solve the SOC test scheduling problem. Experimental results on ITC’02 benchmarks show that the proposed method provides better test time results compared to the Linear-Programming. Keywords: System on chip, test scheduling, cross-entropy method 1. INTRODUCTION In order to shorten the time to market, core based system-on-chip (SOC) design has becomed a widely used technique of integrated circuit design. Compared with system-on-board, work frequency of SOC has improved observably because signal transfers delay is avoid. However, the testing of SOC and the reusable cores becomes a bottleneck of the SOC development. The SOC test includes test information exchange mechanism, test wrapper generation, test access mechanism (TAM) design, test controller design, test schedulin g and test integration, etc. Among the SOC test issues, the test scheduling is one of the most important challenges. Many works have forced on core test scheduling to minimize the overall testing time, in [7], the test scheduling is mapped to the linear programming (LP) problem, but the computation time is too long. In this paper, we use a cross-entropy (CE) method, which is based on probability density function, to solve the test scheduling problem. The paper is organized as follows. In section II, the test scheduling problem is briefly described. We formulate the problem of test scheduling using CE method in section III. Experimental results are given in section IV, and section V concludes the paper.

Network on chip (NoC) is a new design paradigm for building scalable core-based systems on chip (SoC). Multithreading is a technique for hiding long latencies of memory accesses, through the overlapped execution of several threads. In this paper, we make a case for using multi-threaded processors (MTP) as resources in NoC and describe a methodology for off-line mapping and scheduling of concurrent applications to NoC with MTPs. The experimental results show a speedup of 15% on average for a 2/spl times/2 NoC when using two MTPs with 3-thread contexts instead of two general processors (GP).

Application of contactless ultrasound toward automated inspection of concrete structures

Modern embedded Systems-on-Chips (SOCs) will allow the system designer to customize Intellectual Property (IP) cores (fixed and programmable), together with custom logic and large amounts of embedded memory. As the software content in these emerging embedded SOCs begins to dominate the SOC design process, there is a critical need for support of an integrated software development environment (including compilers, simulators and debuggers). Furthermore, since many characteristics of these processor core IPs (e.g., instruction-sets, memory configurations) are increasingly customizable, the entire software toolkit chain needs to be customized and generated to support both early design space exploration (for performance, power and cost constraints), as well as high-qualify software generation. This paper first surveys recent efforts in Architecture Description Languages (ADLs) used to perform early validation and exploration of SOC architectures. The second part of the paper focuses on approaches to software toolkit generation that automatically produce the software infrastructure (e.g., compilers, simulators, debuggers) which will enable true hardware/software codesign of these emerging embedded SOCs.

With the advances in semiconductor and circuit integrated technologies, the number of IP cores that can be integrated on one chip is becoming larger and larger. The traditional bus interconnection method of System on Chip (SoC) cannot meet the performance requirements of the Multi Processor System on Chip (MPSoC). Network on Chip (NoC) has improved the interconnect performance of IP cores. However, the conventional metallic interconnection constrains NoC to make greater improvement, while the mature of optical device integrated technology makes the trend of applying optical interconnection technology to chip promising. This paper proposes a cluster-based reconfigurable optical network on chip architecture (CRONoC), which uses a high bandwidth optical circuit switching network to transmit the inter-cluster data and an electrical packet switching network to control the optical network and transmit the intra-cluster data. By activating the resonators in the proposed inter-cluster crossbar structure, the topology is reconfigurable. Employing the proposed routing algorithm, the maximum distance of the network is reduced to 3 for the 64 core CRONoC. Finally, the performance of CRONoC in terms of end to end latency and network throughput under different traffic patterns is evaluated with OPNET. The simulation results show that the CRONoC architecture is suitable for the local and collective communications.

Over the years, system on chip (SoC) designs have evolved extensively sophisticated in order to fulfil the need of increasing complexity of running applications driven by the advancement of VLSI technology. The next generation multiprocessor system on chip (MPSoC) integrates hundreds of processing elements on a single chip, expected to achieve high performance, low latency, and low-power consumption. Tiled chip multicore processors (TCMP) with network on chip (NoC) have become a foundation for the computation critical embedded and real-time systems. Faster time-to-market restraint and business competition compelled manufacturers to look for the prospects of manufacturing SoCs integrated with various third party intellectual property (3PIP). Usage of 3PIP gave rise to exploit the underlying interconnect while adding some unwanted malicious circuit known as hardware trojan (HT), making NoC vulnerable to get attacked. A tiniest manipulation of any communication attribute by HT can degrade the overall behaviour of the system significantly while impacting NoC performance metrics. In this paper, we present one of such study considering HT malign behaviour of manipulating the output port of each incoming flit from specific ports once genuine route computation takes place and re-directs all to one port causing disruption in tile communication.The proposed HT is intermittent in nature and activates for few cycles. We study the behaviour of proposed confluence attack and analyze its impact over network level. The empirical evaluation exhibits the misbehaviour of the packet communication in terms of wrong usage of VCs and extra hop distance overhead. To validate the proposed work, various performance metrics like buffer utilization, virtual channel utilization, number of flits processed, link utilization, and the like are analyzed. We also show that such HTs are difficult to detect due to marginal increase at malicious port traffic leaving no trace of malicious conduct.

This paper considers the problem of testing VLSI integrated circuits in minimum time without exceeding their power ratings during test. We use a resource graph formulation for the test problem. The solution requires finding a power-constrained schedule of tests. Two formulations of this problem are given as follows: (1) scheduling equal length tests with power constraints and (2) scheduling unequal length tests with power constraints. Optimum solutions are obtained for both formulations. Algorithms consist of four basic steps. First, a test compatibility graph is constructed from the resource graph. Second, the test compatibility graph is used to identify a complete set of time compatible tests with power dissipation information associated with each test. Third, from the set of compatible tests, lists of power compatible tests are extracted. Finally, a minimum cover table approach is used to find an optimum schedule of power compatible tests.

The PowerPC® 405LP system-on-a-chip (SoC) processor, which was developed for high-content, battery-powered application space, provides dynamic voltage-scaling and on-the-fly frequency-scaling capabilities that allow the system and applications to adapt to changes in their performance demands and power constraints during operation. The 405LP operates over a voltage supply range of 1.95 to 0.9 V with a range of power efficiencies of 1.0 to 3.9 MIPS/mW when executing the Dhrystone benchmark. Operating system and application software support allow the applications to take full advantage of the energy-efficiency capabilities of the SoC. This paper describes the organization of the SoC design, details the capabilities provided in the design to match the performance and power consumption with the need of the application, describes how these capabilities are employed, and presents measured results for the PowerPC 405LP processor.

With the development of deep learning, the accuracy of face recognition has been significantly improved. Current face recognition systems are mostly designed for CPU or GPU platforms, and faces significant latency and power constraints when migrated to embedded devices. In this live demonstration, a real-time face recognition system based on FPGA System-on-Chip (SoC) platforms is presented. To achieve real-time processing, the face recognition algorithm based on convolutional neural network is optimized first to a hardware-friendly network model and is accelerated on FPGA, while the face detection and face alignment are implemented on ARM. The latency of the entire system is 52 ms, and the face recognition accuracy on the LWF data set reaches 99.05%.

A new flexible, hierarchical and distributed power-constrained embedded memory built-in self-test (BIST) architecture for complex and heterogeneous systems-on-a-chip (SOCs) is presented. The proposed architecture consists of a shared technology-independent BIST controller, low area and low power memory BIST wrappers and serial interconnect between them for low routing-overhead. Due to its flexibility, in addition to reducing routing complexity and achieving high test concurrency under power constraints, the presented solution can simultaneously support multiple test algorithms for heterogeneous memories, as well as embed custom test algorithms required for new memory faults.

We present a mathematical model for the problem of scheduling tests for core-based system-on-chip (SOC) VLSI designs. Given a set of tests for each core in the SOC and a set of test resources (e.g., test access mechanisms (TAM)), we determine the test plan for the application of the tests to the SOC. Test planning in this paper refers to the combined activities of test access architecture partitioning and test scheduling. These activities must be performed in conjunction as the choice of the test access architecture influences the test schedule. We justify the formulation of test scheduling w.r.t. minimum average completion time criterion as compared to minimum makespan. We show that then the problem of scheduling tests on TAMs can be mapped onto a graph theoretic problem which has a polynomial time optimal solution. We have implemented our algorithm as a test planner tool TPLAN. We present the theoretical analysis of our approach in this paper, and compare our results against those published earlier using integer linear programming techniques with encouraging results.