76 research outputs found

    Process-variation aware mapping of real-time streaming applications to MPSoCs for improved yield

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    Abstractโ€”As technology scales, the impact of process variation on the maximum supported frequency (FMAX) of individual cores in a MPSoC becomes more pronounced. Task allocation without variation-aware performance analysis can result in a significant loss in yield, defined as the number of manufactured chips satisfying the application timing requirement. We propose variation-aware task allocation for real-time streaming applica-tions modeled as task graphs. Our solutions are primarily based on the throughput requirement, which is the most important timing requirement in many real-time streaming applications. The three main contributions of this paper are: 1) Using data flow graphs that are well-suited for modeling and analysis of real-time streaming applications, we explicitly model task execution both in terms of clock cycles (which is independent of variation) and seconds (which does depend on the variation of the resource), which we connect by an explicit binding. 2) We present two approaches for optimizing the yield. The approaches give different results at different costs. 3) We present exhaustive and heuristic algorithms that implement the optimization approaches. Our variation-aware mapping algorithms are tested on models of real applications, and are compared to the mapping methods that are unaware of hardware variation. Our results demonstrate yield improvements of up to 50 % with an average of 31%, showing the effectiveness of our approaches. Index Termsโ€”Process variation, Multiprocessor System-on

    Lifetime reliability of multi-core systems: modeling and applications.

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    Huang, Lin.Thesis (M.Phil.)--Chinese University of Hong Kong, 2011.Includes bibliographical references (leaves 218-232).Abstracts in English and Chinese.Abstract --- p.iAcknowledgement --- p.ivChapter 1 --- Introduction --- p.1Chapter 1.1 --- Preface --- p.1Chapter 1.2 --- Background --- p.5Chapter 1.3 --- Contributions --- p.6Chapter 1.3.1 --- Lifetime Reliability Modeling --- p.6Chapter 1.3.2 --- Simulation Framework --- p.7Chapter 1.3.3 --- Applications --- p.9Chapter 1.4 --- Thesis Outline --- p.10Chapter I --- Modeling --- p.12Chapter 2 --- Lifetime Reliability Modeling --- p.13Chapter 2.1 --- Notation --- p.13Chapter 2.2 --- Assumption --- p.16Chapter 2.3 --- Introduction --- p.16Chapter 2.4 --- Related Work --- p.19Chapter 2.5 --- System Model --- p.21Chapter 2.5.1 --- Reliability of A Surviving Component --- p.22Chapter 2.5.2 --- Reliability of a Hybrid k-out-of-n:G System --- p.26Chapter 2.6 --- Special Cases --- p.31Chapter 2.6.1 --- Case I: Gracefully Degrading System --- p.31Chapter 2.6.2 --- Case II: Standby Redundant System --- p.33Chapter 2.6.3 --- Case III: l-out-of-3:G System with --- p.34Chapter 2.7 --- Numerical Results --- p.37Chapter 2.7.1 --- Experimental Setup --- p.37Chapter 2.7.2 --- Experimental Results and Discussion --- p.40Chapter 2.8 --- Conclusion --- p.43Chapter 2.9 --- Appendix --- p.44Chapter II --- Simulation Framework --- p.47Chapter 3 --- AgeSim: A Simulation Framework --- p.48Chapter 3.1 --- Introduction --- p.48Chapter 3.2 --- Preliminaries and Motivation --- p.51Chapter 3.2.1 --- Prior Work on Lifetime Reliability Analysis of Processor- Based Systems --- p.51Chapter 3.2.2 --- Motivation of This Work --- p.53Chapter 3.3 --- The Proposed Framework --- p.54Chapter 3.4 --- Aging Rate Calculation --- p.57Chapter 3.4.1 --- Lifetime Reliability Calculation --- p.58Chapter 3.4.2 --- Aging Rate Extraction --- p.60Chapter 3.4.3 --- Discussion on Representative Workload --- p.63Chapter 3.4.4 --- Numerical Validation --- p.65Chapter 3.4.5 --- Miscellaneous --- p.66Chapter 3.5 --- Lifetime Reliability Model for MPSoCs with Redundancy --- p.68Chapter 3.6 --- Case Studies --- p.70Chapter 3.6.1 --- Dynamic Voltage and Frequency Scaling --- p.71Chapter 3.6.2 --- Burst Task Arrival --- p.75Chapter 3.6.3 --- Task Allocation on Multi-Core Processors --- p.77Chapter 3.6.4 --- Timeout Policy on Multi-Core Processors with Gracefully Degrading Redundancy --- p.78Chapter 3.7 --- Conclusion --- p.79Chapter 4 --- Evaluating Redundancy Schemes --- p.83Chapter 4.1 --- Introduction --- p.83Chapter 4.2 --- Preliminaries and Motivation --- p.85Chapter 4.2.1 --- Failure Mechanisms --- p.85Chapter 4.2.2 --- Related Work and Motivation --- p.86Chapter 4.3 --- Proposed Analytical Model for the Lifetime Reliability of Proces- sor Cores --- p.88Chapter 4.3.1 --- "Impact of Temperature, Voltage, and Frequency" --- p.88Chapter 4.3.2 --- Impact of Workloads --- p.92Chapter 4.4 --- Lifetime Reliability Analysis for Multi-core Processors with Vari- ous Redundancy Schemes --- p.95Chapter 4.4.1 --- Gracefully Degrading System (GDS) --- p.95Chapter 4.4.2 --- Processor Rotation System (PRS) --- p.97Chapter 4.4.3 --- Standby Redundant System (SRS) --- p.98Chapter 4.4.4 --- Extension to Heterogeneous System --- p.99Chapter 4.5 --- Experimental Methodology --- p.101Chapter 4.5.1 --- Workload Description --- p.102Chapter 4.5.2 --- Temperature Distribution Extraction --- p.102Chapter 4.5.3 --- Reliability Factors --- p.103Chapter 4.6 --- Results and Discussions --- p.103Chapter 4.6.1 --- Wear-out Rate Computation --- p.103Chapter 4.6.2 --- Comparison on Lifetime Reliability --- p.105Chapter 4.6.3 --- Comparison on Performance --- p.110Chapter 4.6.4 --- Comparison on Expected Computation Amount --- p.112Chapter 4.7 --- Conclusion --- p.118Chapter III --- Applications --- p.119Chapter 5 --- Task Allocation and Scheduling for MPSoCs --- p.120Chapter 5.1 --- Introduction --- p.120Chapter 5.2 --- Prior Work and Motivation --- p.122Chapter 5.2.1 --- IC Lifetime Reliability --- p.122Chapter 5.2.2 --- Task Allocation and Scheduling for MPSoC Designs --- p.124Chapter 5.3 --- Proposed Task Allocation and Scheduling Strategy --- p.126Chapter 5.3.1 --- Problem Definition --- p.126Chapter 5.3.2 --- Solution Representation --- p.128Chapter 5.3.3 --- Cost Function --- p.129Chapter 5.3.4 --- Simulated Annealing Process --- p.130Chapter 5.4 --- Lifetime Reliability Computation for MPSoC Embedded Systems --- p.133Chapter 5.5 --- Efficient MPSoC Lifetime Approximation --- p.138Chapter 5.5.1 --- Speedup Technique I - Multiple Periods --- p.139Chapter 5.5.2 --- Speedup Technique II - Steady Temperature --- p.139Chapter 5.5.3 --- Speedup Technique III - Temperature Pre- calculation --- p.140Chapter 5.5.4 --- Speedup Technique IV - Time Slot Quantity Control --- p.144Chapter 5.6 --- Experimental Results --- p.144Chapter 5.6.1 --- Experimental Setup --- p.144Chapter 5.6.2 --- Results and Discussion --- p.146Chapter 5.7 --- Conclusion and Future Work --- p.152Chapter 6 --- Energy-Efficient Task Allocation and Scheduling --- p.154Chapter 6.1 --- Introduction --- p.154Chapter 6.2 --- Preliminaries and Problem Formulation --- p.157Chapter 6.2.1 --- Related Work --- p.157Chapter 6.2.2 --- Problem Formulation --- p.159Chapter 6.3 --- Analytical Models --- p.160Chapter 6.3.1 --- Performance and Energy Models for DVS-Enabled Pro- cessors --- p.160Chapter 6.3.2 --- Lifetime Reliability Model --- p.163Chapter 6.4 --- Proposed Algorithm for Single-Mode Embedded Systems --- p.165Chapter 6.4.1 --- Task Allocation and Scheduling --- p.165Chapter 6.4.2 --- Voltage Assignment for DVS-Enabled Processors --- p.168Chapter 6.5 --- Proposed Algorithm for Multi-Mode Embedded Systems --- p.169Chapter 6.5.1 --- Feasible Solution Set --- p.169Chapter 6.5.2 --- Searching Procedure for a Single Mode --- p.171Chapter 6.5.3 --- Feasible Solution Set Identification --- p.171Chapter 6.5.4 --- Multi-Mode Combination --- p.177Chapter 6.6 --- Experimental Results --- p.178Chapter 6.6.1 --- Experimental Setup --- p.178Chapter 6.6.2 --- Case Study --- p.180Chapter 6.6.3 --- Sensitivity Analysis --- p.181Chapter 6.6.4 --- Extensive Results --- p.183Chapter 6.7 --- Conclusion --- p.185Chapter 7 --- Customer-Aware Task Allocation and Scheduling --- p.186Chapter 7.1 --- Introduction --- p.186Chapter 7.2 --- Prior Work and Problem Formulation --- p.188Chapter 7.2.1 --- Related Work and Motivation --- p.188Chapter 7.2.2 --- Problem Formulation --- p.191Chapter 7.3 --- Proposed Design-Stage Task Allocation and Scheduling --- p.192Chapter 7.3.1 --- Solution Representation and Moves --- p.193Chapter 7.3.2 --- Cost Function --- p.196Chapter 7.3.3 --- Impact of DVFS --- p.198Chapter 7.4 --- Proposed Algorithm for Online Adjustment --- p.200Chapter 7.4.1 --- Reliability Requirement for Online Adjustment --- p.201Chapter 7.4.2 --- Analytical Model --- p.203Chapter 7.4.3 --- Overall Flow --- p.204Chapter 7.5 --- Experimental Results --- p.205Chapter 7.5.1 --- Experimental Setup --- p.205Chapter 7.5.2 --- Results and Discussion --- p.207Chapter 7.6 --- Conclusion --- p.211Chapter 7.7 --- Appendix --- p.211Chapter 8 --- Conclusion and Future Work --- p.214Chapter 8.1 --- Conclusion --- p.214Chapter 8.2 --- Future Work --- p.215Bibliography --- p.23

    Worst-case temporal analysis of real-time dynamic streaming applications

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    DeSyRe: on-Demand System Reliability

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    The DeSyRe project builds on-demand adaptive and reliable Systems-on-Chips (SoCs). As fabrication technology scales down, chips are becoming less reliable, thereby incurring increased power and performance costs for fault tolerance. To make matters worse, power density is becoming a significant limiting factor in SoC design, in general. In the face of such changes in the technological landscape, current solutions for fault tolerance are expected to introduce excessive overheads in future systems. Moreover, attempting to design and manufacture a totally defect and fault-free system, would impact heavily, even prohibitively, the design, manufacturing, and testing costs, as well as the system performance and power consumption. In this context, DeSyRe delivers a new generation of systems that are reliable by design at well-balanced power, performance, and design costs. In our attempt to reduce the overheads of fault-tolerance, only a small fraction of the chip is built to be fault-free. This fault-free part is then employed to manage the remaining fault-prone resources of the SoC. The DeSyRe framework is applied to two medical systems with high safety requirements (measured using the IEC 61508 functional safety standard) and tight power and performance constraints

    Low power architectures for streaming applications

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    Design Space Exploration and Resource Management of Multi/Many-Core Systems

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    The increasing demand of processing a higher number of applications and related data on computing platforms has resulted in reliance on multi-/many-core chips as they facilitate parallel processing. However, there is a desire for these platforms to be energy-efficient and reliable, and they need to perform secure computations for the interest of the whole community. This book provides perspectives on the aforementioned aspects from leading researchers in terms of state-of-the-art contributions and upcoming trends

    Framework for simulation of fault tolerant heterogeneous multiprocessor system-on-chip

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    Due to the ever growing requirement in high performance data computation, current Uniprocessor systems fall short of hand to meet critical real-time performance demands in (i) high throughput (ii) faster processing time (iii) low power consumption (iv) design cost and time-to-market factors and more importantly (v) fault tolerant processing. Shifting the design trend to MPSOCs is a work-around to meet these challenges. However, developing efficient fault tolerant task scheduling and mapping techniques requires optimized algorithms that consider the various scenarios in Multiprocessor environments. Several works have been done in the past few years which proposed simulation based frameworks for scheduling and mapping strategies that considered homogenous systems and error avoidance techniques. However, most of these works inadequately describe today\u27s MPSOC trend because they were focused on the network domain and didn\u27t consider heterogeneous systems with fault tolerant capabilities; In order to address these issues, this work proposes (i) a performance driven scheduling algorithm (PD SA) based on simulated annealing technique (ii) an optimized Homogenous-Workload-Distribution (HWD) Multiprocessor task mapping algorithm which considers the dynamic workload on processors and (iii) a dynamic Fault Tolerant (FT) scheduling/mapping algorithm to employ robust application processing system. The implementation was accompanied by a heterogeneous Multiprocessor system simulation framework developed in systemC/C++. The proposed framework reads user data, set the architecture, execute input task graph and finally generate performance variables. This framework alleviates previous work issues with respect to (i) architectural flexibility in number-of-processors, processor types and topology (ii) optimized scheduling and mapping strategies and (iii) fault-tolerant processing capability focusing more on the computational domain; A set of random as well as application specific STG benchmark suites were run on the simulator to evaluate and verify the performance of the proposed algorithms. The simulations were carried out for (i) scheduling policy evaluation (ii) fault tolerant evaluation (iii) topology evaluation (iv) Number of processor evaluation (v) Mapping policy evaluation and (vi) Processor Type evaluation. The results showed that PD scheduling algorithm showed marginally better performance than EDF with respect to utilization, Execution-Time and Power factors. The dynamic Fault Tolerant implementation showed to be a viable and efficient strategy to meet real-time constraints without posing significant system performance degradation. Torus topology gave better performance than Tile with respect to task completion time and power factors. Executing highly heterogeneous Tasks showed higher power consumption and execution time. Finally, increasing the number of processors showed a decrease in average Utilization but improved task completion time and power consumption; Based on the simulation results, the system designer can compare tradeoffs between a various design choices with respect to the performance requirement specifications. In general, designing an optimized Multiprocessor scheduling and mapping strategy with added fault tolerant capability will enable to develop efficient Multiprocessor systems which meet future performance goal requirements. This is the substance of this work

    Run-time management for future MPSoC platforms

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    In recent years, we are witnessing the dawning of the Multi-Processor Systemon- Chip (MPSoC) era. In essence, this era is triggered by the need to handle more complex applications, while reducing overall cost of embedded (handheld) devices. This cost will mainly be determined by the cost of the hardware platform and the cost of designing applications for that platform. The cost of a hardware platform will partly depend on its production volume. In turn, this means that ??exible, (easily) programmable multi-purpose platforms will exhibit a lower cost. A multi-purpose platform not only requires ??exibility, but should also combine a high performance with a low power consumption. To this end, MPSoC devices integrate computer architectural properties of various computing domains. Just like large-scale parallel and distributed systems, they contain multiple heterogeneous processing elements interconnected by a scalable, network-like structure. This helps in achieving scalable high performance. As in most mobile or portable embedded systems, there is a need for low-power operation and real-time behavior. The cost of designing applications is equally important. Indeed, the actual value of future MPSoC devices is not contained within the embedded multiprocessor IC, but in their capability to provide the user of the device with an amount of services or experiences. So from an application viewpoint, MPSoCs are designed to ef??ciently process multimedia content in applications like video players, video conferencing, 3D gaming, augmented reality, etc. Such applications typically require a lot of processing power and a signi??cant amount of memory. To keep up with ever evolving user needs and with new application standards appearing at a fast pace, MPSoC platforms need to be be easily programmable. Application scalability, i.e. the ability to use just enough platform resources according to the user requirements and with respect to the device capabilities is also an important factor. Hence scalability, ??exibility, real-time behavior, a high performance, a low power consumption and, ??nally, programmability are key components in realizing the success of MPSoC platforms. The run-time manager is logically located between the application layer en the platform layer. It has a crucial role in realizing these MPSoC requirements. As it abstracts the platform hardware, it improves platform programmability. By deciding on resource assignment at run-time and based on the performance requirements of the user, the needs of the application and the capabilities of the platform, it contributes to ??exibility, scalability and to low power operation. As it has an arbiter function between different applications, it enables real-time behavior. This thesis details the key components of such an MPSoC run-time manager and provides a proof-of-concept implementation. These key components include application quality management algorithms linked to MPSoC resource management mechanisms and policies, adapted to the provided MPSoC platform services. First, we describe the role, the responsibilities and the boundary conditions of an MPSoC run-time manager in a generic way. This includes a de??nition of the multiprocessor run-time management design space, a description of the run-time manager design trade-offs and a brief discussion on how these trade-offs affect the key MPSoC requirements. This design space de??nition and the trade-offs are illustrated based on ongoing research and on existing commercial and academic multiprocessor run-time management solutions. Consequently, we introduce a fast and ef??cient resource allocation heuristic that considers FPGA fabric properties such as fragmentation. In addition, this thesis introduces a novel task assignment algorithm for handling soft IP cores denoted as hierarchical con??guration. Hierarchical con??guration managed by the run-time manager enables easier application design and increases the run-time spatial mapping freedom. In turn, this improves the performance of the resource assignment algorithm. Furthermore, we introduce run-time task migration components. We detail a new run-time task migration policy closely coupled to the run-time resource assignment algorithm. In addition to detailing a design-environment supported mechanism that enables moving tasks between an ISP and ??ne-grained recon??gurable hardware, we also propose two novel task migration mechanisms tailored to the Network-on-Chip environment. Finally, we propose a novel mechanism for task migration initiation, based on reusing debug registers in modern embedded microprocessors. We propose a reactive on-chip communication management mechanism. We show that by exploiting an injection rate control mechanism it is possible to provide a communication management system capable of providing a soft (reactive) QoS in a NoC. We introduce a novel, platform independent run-time algorithm to perform quality management, i.e. to select an application quality operating point at run-time based on the user requirements and the available platform resources, as reported by the resource manager. This contribution also proposes a novel way to manage the interaction between the quality manager and the resource manager. In order to have a the realistic, reproducible and ??exible run-time manager testbench with respect to applications with multiple quality levels and implementation tradev offs, we have created an input data generation tool denoted Pareto Surfaces For Free (PSFF). The the PSFF tool is, to the best of our knowledge, the ??rst tool that generates multiple realistic application operating points either based on pro??ling information of a real-life application or based on a designer-controlled random generator. Finally, we provide a proof-of-concept demonstrator that combines these concepts and shows how these mechanisms and policies can operate for real-life situations. In addition, we show that the proposed solutions can be integrated into existing platform operating systems

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    ํ•™์œ„๋…ผ๋ฌธ (๋ฐ•์‚ฌ)-- ์„œ์šธ๋Œ€ํ•™๊ต ๋Œ€ํ•™์› : ์ „๊ธฐยท์ปดํ“จํ„ฐ๊ณตํ•™๋ถ€, 2014. 8. ํ•˜์ˆœํšŒ.๊ธฐ์ˆ ์ด ๋ฐœ์ „ํ•จ์— ๋”ฐ๋ผ ํ•˜๋‚˜์˜ ์นฉ ์•ˆ์— ์ง‘์ ๋˜๋Š” ํ”„๋กœ์„ธ์„œ์˜ ๊ฐฏ์ˆ˜๊ฐ€ ์ ์  ์ฆ๊ฐ€ํ•˜๊ฒŒ ๋˜์—ˆ๋‹ค. ๋˜ํ•œ, ์‘์šฉ๋“ค์˜ ๋ณด๋‹ค ๋†’์€ ์—ฐ์‚ฐ ๋Šฅ๋ ฅ์— ๋Œ€ํ•œ ์š”๊ตฌ๋กœ ์ธํ•ด ๋งค๋‹ˆ์ฝ”์–ด ๊ฐ€์†๊ธฐ๋Š” ์‹œ์Šคํ…œ-์˜จ-์นฉ์—์„œ ์ค‘์š”ํ•œ ์—ฐ์‚ฐ ์žฅ์น˜๊ฐ€ ๋˜์—ˆ๋‹ค. ์‹œ์Šคํ…œ์˜ ์ƒํƒœ๊ฐ€ ์—ฌ๋Ÿฌ๊ฐ€์ง€ ์š”์ธ์— ์˜ํ•ด ๋™์ ์œผ๋กœ ๋ณ€ํ•˜๊ธฐ ๋•Œ๋ฌธ์—, ์‹œ์Šคํ…œ ์ˆ˜ํ–‰์ค‘์— ๊ทธ๋Ÿฌํ•œ ๊ฐ€์†๊ธฐ๋ฅผ ํšจ๊ณผ์ ์œผ๋กœ ๋‹ค๋ฃจ๋Š” ๊ฒƒ์€ ๋งค์šฐ ์–ด๋ ค์šด ๋ฌธ์ œ์ด๋‹ค. ์‹œ์Šคํ…œ ์ˆ˜์ค€์—์„œ๋Š” ์‘์šฉ๋“ค์ด ์‚ฌ์šฉ์ž์˜ ์š”๊ตฌ์— ๋”ฐ๋ผ ์‹œ์ž‘ ๋˜๋Š” ์ข…๋ฃŒ๊ฐ€ ๋˜๊ณ , ์‘์šฉ ๋ ˆ๋ฒจ์—์„œ๋Š” ์‘์šฉ ์ž์ฒด์˜ ๋™์ž‘์ด ์ž…๋ ฅ ๋ฐ์ดํƒ€๋‚˜ ์ˆ˜ํ–‰๋ชจ๋“œ์— ๋”ฐ๋ผ ๋™์ ์œผ๋กœ ๋ณ€ํ•˜๊ฒŒ ๋œ๋‹ค. ์•„ํ‚คํ…์ฒ˜ ์ˆ˜์ค€์—์„œ๋Š” ํ”„๋กœ์„ธ์„œ์˜ ์˜๊ตฌ ๊ณ ์žฅ์œผ๋กœ ์ธํ•ด ํ•˜๋“œ์›จ์–ด ์ปดํฌ๋„ŒํŠธ์˜ ์‚ฌ์šฉ ๊ฐ€๋Šฅํ•œ ์ƒํ™ฉ์ด ๋ณ€ํ•˜๊ฒŒ ๋œ๋‹ค. ๋ณธ ํ•™์œ„๋…ผ๋ฌธ์—์„œ๋Š” ๊ฐ€์†๊ธฐ๋ฅผ ๋‹ค๋ฃจ๋Š”๋ฐ ์žˆ์–ด์„œ์˜ ์œ„์™€ ๊ฐ™์€ ์–ด๋ ค์›€๋“ค์„ ํ•ด๊ฒฐํ•˜๊ธฐ ์œ„ํ•ด ์„ธ๊ฐ€์ง€ ๊ธฐ๋ฒ•์„ ์ œ์‹œํ•˜์˜€๋‹ค. ์ฒซ๋ฒˆ์งธ ๊ธฐ๋ฒ•์€ ํ”„๋กœ์„ธ์„œ์˜ ์˜๊ตฌ ๊ณ ์žฅ์ด ๋ฐœ์ƒํ•˜์˜€์„ ๋•Œ, ์ „์ฒด ์‘์šฉ๋“ค์„ ์‹œ๊ฐ„ ์ œ์•ฝ ํ•˜์— ์ฒ˜๋ฆฌ๋Ÿ‰์˜ ์ €ํ•˜๋ฅผ ์ตœ์†Œํ™”ํ•˜๋ฉฐ ์žฌ์Šค์ผ€์ฅด์„ ํ•˜๋Š” ๊ฒƒ์ด๋‹ค. ์ตœ์ ์˜ ์žฌ์Šค์ผ€์ฅด ๊ฒฐ๊ณผ๋“ค์€ ์ง„ํ™” ์•Œ๊ณ ๋ฆฌ์ฆ˜์„ ์ด์šฉํ•˜์—ฌ ์ปดํŒŒ์ผ ์‹œ์—, ๊ฐ๊ฐ์˜ ํ”„๋กœ์„ธ์„œ ๊ณ ์žฅ ์ƒํ™ฉ์— ๋”ฐ๋ผ ์ค€๋น„๊ฐ€ ๋œ๋‹ค. ์ˆ˜ํ–‰ ์‹œ๊ฐ„์— ํ”„๋กœ์„ธ์„œ ๊ณ ์žฅ์ด ๊ฐ์ง€๋˜๋ฉด, ์ •์ƒ์ ์œผ๋กœ ๋™์ž‘ํ•˜๋Š” ํ”„๋กœ์„ธ์„œ๋“ค์ด ์ €์žฅ๋œ ์Šค์ผ€์ฅด์„ ๊ฐ€์ง€๊ณ  ํƒœ์Šคํฌ ์ด์ฃผ๋ฅผ ์ˆ˜ํ–‰ํ•œ ํ›„ ํƒœ์Šคํฌ๋“ค์˜ ๋‚˜๋จธ์ง€ ์ˆ˜ํ–‰์„ ์ง€์†ํ•œ๋‹ค. ์ด ๊ธฐ๋ฒ•์—์„œ๋Š” ๋˜ํ•œ ๋” ์ข‹์€ ์„ฑ๋Šฅ์„ ์–ป๊ธฐ ์œ„ํ•ด, ์„ ์ , ๋น„์„ ์  ๋ฐ ์œตํ•ฉ ์ด์ฃผ ์ •์ฑ…์ด ์ œ์•ˆ๋˜์—ˆ๋‹ค. ์ œ์•ˆ๋œ ๊ธฐ๋ฒ•์˜ ๊ฐ€๋Šฅ์„ฑ์€ ์‹ค์ œ ๋””์ง€ํ„ธ ์‹ ํ˜ธ์ฒ˜๋ฆฌ ์‘์šฉ๋“ค๊ณผ ์ž„์˜๋กœ ์ƒ์„ฑ๋œ ์‘์šฉ๋“ค์— ๋Œ€ํ•ด ์‹œ๊ฐ„์ œ์•ฝ๊ณผ ๋‹ค์–‘ํ•œ ํ”„๋กœ์„ธ์„œ ๊ณ ์žฅ ์ƒํ™ฉ์— ๋Œ€ํ•ด ๊ฒ€์ฆ๋˜์—ˆ๋‹ค. ๋‘ ๋ฒˆ์งธ๋กœ ์ œ์•ˆ๋œ ๊ธฐ๋ฒ•์€ ๋ณตํ•ฉ ์ž์› ๊ด€๋ฆฌ ๊ธฐ๋ฒ•์œผ๋กœ, ์ฒซ๋ฒˆ์งธ ๊ธฐ๋ฒ•์—์„œ ๋‹ค๋ฃฌ ํ”„๋กœ์„ธ์„œ ์˜๊ตฌ๊ณ ์žฅ ๋ฟ๋งŒ ์•„๋‹ˆ๋ผ, ๋™๊ธฐํ™” ๋ฐ์ดํƒ€-ํ๋ฆ„ ๊ทธ๋ž˜ํ”„๋กœ ๊ธฐ์ˆ ๋œ ์—ฌ๋Ÿฌ ์‘์šฉ๋“ค๊ณผ ์‘์šฉ๋“ค์˜ ๋™์  ์–‘์ƒ์„ ๋‹ค๋ฃจ๋Š” ๊ฒƒ๊นŒ์ง€๋กœ ํ™•์žฅ์ด ๋œ ๊ฒƒ์ด๋‹ค. ์ œ์•ˆ๋œ ๊ธฐ๋ฒ•์—์„œ๋Š”, ์šฐ์„  ์„ค๊ณ„ ์ˆ˜์ค€์—์„œ ํ• ๋‹น๋˜๋Š” ํ”„๋กœ์„ธ์„œ์˜ ๊ฐฏ์ˆ˜๋ฅผ ๋ณ€ํ™”์‹œ์ผœ๊ฐ€๋ฉด์„œ ๋™๊ธฐํ™”๋œ ๋ฐ์ดํƒ€-ํ๋ฆ„ ๊ทธ๋ž˜ํ”„๋“ค์˜ ์ฒ˜๋ฆฌ๋Ÿ‰์ด ์ตœ๋Œ€๋กœ ์–ป์–ด์ง€๋Š” ๋งคํ•‘ ๊ฒฐ๊ณผ๋“ค์„ ์–ป๋Š”๋‹ค. ๊ทธ๋ฆฌ๊ณ ๋‚˜์„œ ์ˆ˜ํ–‰ ์‹œ๊ฐ„์—๋Š” ๋ฏธ๋ฆฌ ๊ณ„์‚ฐ๋œ ๋งคํ•‘ ์ •๋ณด๋“ค์„ ๊ฐ€์ง€๊ณ  ์ˆ˜ํ–‰์ค‘์ธ ์‘์šฉ๋“ค์˜ ๋งคํ•‘์„, ๋™์ ์ธ ์‹œ์Šคํ…œ ๋ณ€ํ™”๊ฐ€ ๋ฐœ์ƒํ•  ๋•Œ๋งˆ๋‹ค ์ ์šฉํ•˜๊ฒŒ ๋œ๋‹ค. ์ œ์•ˆ๋œ ์ž์› ๊ด€๋ฆฌ ๊ธฐ๋ฒ•์€ Noxim์ด๋ผ๋Š” ๋„คํŠธ์›Œํฌ-์˜จ-์นฉ ์‹œ๋ฎฌ๋ ˆ์ดํ„ฐ ์œ„์—์„œ ๊ตฌํ˜„์ด ๋˜์—ˆ์œผ๋ฉฐ, ์‹คํ—˜ ๊ฒฐ๊ณผ๋“ค์€ ์ œ์•ˆ๋œ ๊ธฐ๋ฒ•์ด ์ตœ์‹ ์˜ ๋‹ค๋ฅธ ๊ธฐ๋ฒ•๋“ค๊ณผ ๋น„๊ตํ•˜์—ฌ ๋” ์ข‹์€ ์„ฑ๋Šฅ์„ ๋ณด์˜€๋‹ค. ๋งˆ์ง€๋ง‰์œผ๋กœ๋Š”, ์‹œ์Šคํ…œ์˜ ์„ฑ๋Šฅ์„ ์‹œ์Šคํ…œ-์˜จ-์นฉ ์ œ์ž‘ ์ด์ „์— ๋ณด๋‹ค ์ •ํ™•ํ•˜๊ฒŒ ํ‰๊ฐ€ํ•˜๊ธฐ ์œ„ํ•ด์„œ, ๋‘ ๋ฒˆ์งธ ๊ธฐ๋ฒ•์„ ๊ตฌํ˜„ํ•œ ์†Œํ”„ํŠธ์›จ์–ด ํ”Œ๋žซํผ์ด ๋งค๋‹ˆ์ฝ”์–ด ์•„ํ‚คํ…์ฒ˜๋ฅผ ๋Œ€์ƒ์œผ๋กœ ์ œ์•ˆ๋˜์—ˆ๋‹ค. ๊ธฐ์กด์˜ ๋งค๋‹ˆ์ฝ”์–ด ์•„ํ‚คํ…์ฒ˜๋ฅผ ๋Œ€์ƒ์œผ๋กœ ํ•œ ์—ฐ๊ตฌ๋“ค์€ ์ฃผ๋กœ ์ƒ์œ„ ์ˆ˜์ค€์˜ ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ๋ชจ๋ธ์„ ์‚ฌ์šฉํ•˜์—ฌ ์„ฑ๋Šฅ์„ ์ธก์ •ํ•˜์˜€๊ธฐ ๋•Œ๋ฌธ์—, ์‹ค์ œ ์„ฑ๋Šฅ๊ณผ ์‹œ๋ฎฌ๋ ˆ์ด์…˜ ์„ฑ๋Šฅ์ด ์–ผ๋งˆ๋‚˜ ์ฐจ์ด๊ฐ€ ๋‚ ์ง€๋ฅผ ์ •ํ™•ํ•˜๊ฒŒ ์•Œ ์ˆ˜๊ฐ€ ์—†์—ˆ๋‹ค. ์ด๋Ÿฌํ•œ ํ•œ๊ณ„๋ฅผ ๊ทน๋ณตํ•˜๊ธฐ ์œ„ํ•˜์—ฌ ์†Œํ”„ํŠธ์›จ์–ด ํ”Œ๋žซํผ๊ณผ, ๊ฐ€์ƒ ํ”„๋กœํ† ํƒ€์ดํ•‘ ์‹œ์Šคํ…œ ๋ฐ ์ œ์˜จ ์—๋ฎฌ๋ ˆ์ด์…˜ ์‹œ์Šคํ…œ์—์„œ์˜ ํ”Œ๋žซํผ ๊ตฌํ˜„ ๋ฐฉ๋ฒ•์ด ์ œ์•ˆ์ด ๋˜์—ˆ๋‹ค. ์ด๋Ÿฌํ•œ ์‹ค์ œ ์‹œ์Šคํ…œ ๊ตฌํ˜„์„ ํ†ตํ•˜์—ฌ ์ œ์•ˆ๋œ ๋ณตํ•ฉ ์ž์› ๊ด€๋ฆฌ ๊ธฐ๋ฒ•์—์„œ์˜ ๋‹ค์–‘ํ•œ ๋™์  ๋น„์šฉ๋“ค์ด ์ •ํ™•ํ•˜๊ฒŒ ์ถ”์‚ฐ์ด ๋  ์ˆ˜ ์žˆ์—ˆ๋‹ค. ์‹คํ—˜์—์„œ๋Š” ์ œ์•ˆ๋œ ์†Œํ”„ํŠธ์›จ์–ด ๊ธฐ๋ฒ•์ด ํƒœ์Šคํฌ๋“ค์˜ ๋™์  ๋งคํ•‘๊ณผ ์ฒดํฌ-ํฌ์ธํŒ…์„ ํ†ตํ•œ ํ”„๋กœ์„ธ์„œ ์˜๊ตฌ ๊ณ ์žฅ์„ ํšจ๊ณผ์ ์œผ๋กœ ๊ฐ๋‚ดํ•  ์ˆ˜ ์žˆ์Œ์„ ๋ณด์˜€๋‹ค.Owing to the incessant technology improvement, the number of processors integrated into a single chip increases consistently, integrating more and more applications. Also, demand for higher computing capability for applications makes a many-core accelerator become an important computing resource in a system-on-chip. Efficient handling of the accelerator at run-time, however, is very challenging because the system status is subject to change dynamically by various factors. At the system level, the set of applications running concurrently may change according to user request. At the application level, the application behavior may change dynamically depending on input data or operation mode. At the architecture level, hardware resource availability may vary since hardware components may experience transient or permanent failures. In this thesis, to resolve the difficulties in handling many-core accelerator, three techniques are proposed. The first technique is the re-scheduling of the entire application to minimize throughput degradation under a latency constraint when a permanent processor failure occurs. Sub-optimal re-scheduling results using a genetic algorithm for each scenario of processor failures are obtained at compile-time. If a failure is detected at run-time, the live processors obtain the saved schedule, perform task transfer, and execute the remaining tasks of the current iteration. In this technique, preemptive and non-preemptive migration policies and a hybrid policy are proposed to obtain better performance. The viability of the proposed technique with real-life DSP applications as well as randomly generated graphs under timing constraints and random fault scenarios are shown through experiments. The second technique is a hybrid resource management scheme, expanded version of the first technique that also handles multi-applications specified as SDF graph and their relevant dynamisms such as application/task arrivals/ends as well as processor permanent failures. In the proposed technique, at design-time, throughput-maximized mappings of each SDF graph by varying the number of allocated processors are determined. Then, at run-time, the pre-computed mapping information is exploited to adjust the mapping of active applications to the processors without user intervention on the system status change. The proposed resource management is evaluated through intensive experiments with an in-house simulator built on top of Noxim, a Network-on-Chip simulator. Experimental results show the enhanced adaptability to dynamic system status change compared to other state-of-the-art approaches. Finally, the software platform for a homogeneous many-core architecture that implements the second technique is proposed to evaluate the system performance more accurately before SoC fabrication. Existing approaches usually use a high-level simulation model to estimate the performance without knowing how much actual performance will be deviated from the estimation. To overcome the limitation, the software platform is proposed and implementation details on a virtual prototyping system and on an emulation system realized with an Intel Xeon-Phi coprocessor are presented. Actual implementation enables us to investigate the overheads involved in the hybrid resource management technique in detail, which was not possible in high-level simulation. Experimental results confirm that the proposed software platform adapts to the dynamic workload variation effectively by dynamic mapping of tasks and tolerate unexpected core failures by check-pointing.Abstract i Contents iv List of Figures viii List of Tables xii Chapter 1 Introduction 1 1.1 Motivation . . . . . . . . . . . . 1 1.2 Contribution . . . . . . . . . . . . 5 1.3 Thesis Organization . . . . . . . . . . . 7 Chapter 2 Preliminaries 8 2.1 Application Model . . . . . . . . . . 8 2.2 Architecture Model . . . . . . . . . . 13 2.3 Fault Model . . . . . . . . . . . . 15 2.4 Thesis Overview . . . . . . . . . . . 15 Chapter 3 Fault-aware Task Mapping 17 3.1 Introduction . . . . . . . . . . . . 17 3.2 Related Work . . . . . . . . . . . . 20 3.2.1 Static Approach . . . . . . . . . . 21 3.2.2 Dynamic Approach . . . . . . . . . . 22 3.3 Proposed Task Remapping/Rescheduling Technique . . 23 3.3.1 Remapping Technique . . . . . . . . 23 3.3.2 Rescheduling Technique . . . . . . . . 31 3.4 Experiments . . . . . . . . . . . . . 38 3.4.1 Remapping Results . . . . . . . . 38 3.4.2 Rescheduling Results . . . . . . . . 46 Chapter 4 Fault-aware Resource Management 53 4.1 Introduction . . . . . . . . . . . . 53 4.2 Related Work . . . . . . . . . . . . 54 4.2.1 Static Approach . . . . . . . . . . 55 4.2.2 Dynamic Approach . . . . . . . . . 55 4.2.3 Hybrid Approach . . . . . . . . . . 57 4.2.4 Summary . . . . . . . . . . . . 57 4.3 Background . . . . . . . . . . . . . 58 4.3.1 Energy Model . . . . . . . . . . . 59 4.3.2 Notation . . . . . . . . . . . . 60 4.4 Proposed Resource Management Technique . . . . 61 4.4.1 Motivational Example . . . . . . . . . 61 4.4.2 Overall Procedure . . . . . . . . . . 65 4.4.3 Design-time Analysis . . . . . . . . . 66 4.4.4 Run-time Mapping . . . . . . . . . . 67 4.5 Experiments . . . . . . . . . . . . . 74 4.5.1 Setup . . . . . . . . . . . . . . 74 4.5.2 Analysis of Run-time Overheads . . . . . . 75 4.5.3 Comparison with Other Approaches . . . . 79 Chapter 5 Software Platform for Resource Management 86 5.1 Introduction . . . . . . . . . . . . 86 5.2 Related Work . . . . . . . . . . . . 87 5.3 Overall Structure . . . . . . . . . . . . 88 5.4 Components of Software Platform . . . . . . 89 5.4.1 Application API Layer . . . . . . . . . 89 5.4.2 Communication Interface Module . . . . . 92 5.4.3 Host Interface Layer . . . . . . . . . 93 5.4.4 Memory Management Module . . . . . . 94 5.4.5 Design-time Analysis . . . . . . . . . 94 5.4.6 Slave Manager . . . . . . . . . . . 98 5.5 Software Platform Implementation . . . . . . 99 5.5.1 Scheduling Information . . . . . . . . 100 5.5.2 Function Migration and Execution . . . . . 101 5.5.3 Function Migration and Execution . . . . . 102 5.6 Virtual Prototyping System . . . . . . . . 105 5.7 Xeon Emulation System . . . . . . . . . 106 5.8 Experiments . . . . . . . . . . . . . 107 5.8.1 Setup . . . . . . . . . . . . . . 107 5.8.2 Experiments on the Virtual Prototyping System . . 108 5.8.3 Experiments on the Xeon Emulation System . . . 111 Chapter 6 Conclusion 116 Bibliography 119 Abstract in Korean 130Docto
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