190 research outputs found

    Advanced Timing and Synchronization Methodologies for Digital VLSI Integrated Circuits

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    This dissertation addresses timing and synchronization methodologies that are critical to the design, analysis and optimization of high-performance, integrated digital VLSI systems. As process sizes shrink and design complexities increase, achieving timing closure for digital VLSI circuits becomes a significant bottleneck in the integrated circuit design flow. Circuit designers are motivated to investigate and employ alternative methods to satisfy the timing and physical design performance targets. Such novel methods for the timing and synchronization of complex circuitry are developed in this dissertation and analyzed for performance and applicability.Mainstream integrated circuit design flow is normally tuned for zero clock skew, edge-triggered circuit design. Non-zero clock skew or multi-phase clock synchronization is seldom used because the lack of design automation tools increases the length and cost of the design cycle. For similar reasons, level-sensitive registers have not become an industry standard despite their superior size, speed and power consumption characteristics compared to conventional edge-triggered flip-flops.In this dissertation, novel design and analysis techniques that fully automate the design and analysis of non-zero clock skew circuits are presented. Clock skew scheduling of both edge-triggered and level-sensitive circuits are investigated in order to exploit maximum circuit performances. The effects of multi-phase clocking on non-zero clock skew, level-sensitive circuits are investigated leading to advanced synchronization methodologies. Improvements in the scalability of the computational timing analysis process with clock skew scheduling are explored through partitioning and parallelization.The integration of the proposed design and analysis methods to the physical design flow of integrated circuits synchronized with a next-generation clocking technology-resonant rotary clocking technology-is also presented. Based on the design and analysis methods presented in this dissertation, a computer-aided design tool for the design of rotary clock synchronized integrated circuits is developed

    Linearization of The Timing Analysis and Optimization of Level-Sensitive Circuits

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    This thesis describes a linear programming (LP) formulation applicable to the static timing analysis of large scale synchronous circuits with level-sensitive latches. The automatic timing analysis procedure presented here is composed of deriving the connectivity information, constructing the LP model and solving the clock period minimization problem of synchronous digital VLSI circuits. In synchronous circuits with level-sensitive latches, operation at a reduced clock period (higher clock frequency) is possible by takingadvantage of both non-zero clock skew scheduling and time borrowing. Clock skew schedulingis performed in order to exploit the benefits of nonidentical clock signal delays on circuit timing. The time borrowing property of level-sensitive circuits permits higher operating frequencies compared to edge-sensitivecircuits. Considering time borrowing in the timing analysis, however, introduces non-linearity in this timing analysis. The modified big M (MBM) method is defined in order to transform the non-linear constraints arising in the problem formulation into solvable linear constraints. Equivalent LP model problemsfor single-phase clock synchronization of the ISCAS'89 benchmark circuits are generated and these problems are solved by the industrial LP solver CPLEX. Through the simultaneous application of time borrowing and clock skew scheduling, up to 63% improvements are demonstrated in minimum clock period with respect to zero-skew edge-sensitive synchronous circuits. The timing constraints governing thelevel-sensitive synchronous circuit operation not only solve the clock period minimization problem but also provide a common framework for the general timing analysis of such circuits. The inclusion of additional constraints into the problem formulation in order to meet the timing requirements imposed by specific applicationenvironments is discussed

    Fast algorithms for retiming large digital circuits

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    The increasing complexity of VLSI systems and shrinking time to market requirements demand good optimization tools capable of handling large circuits. Retiming is a powerful transformation that preserves functionality, and can be used to optimize sequential circuits for a wide range of objective functions by judiciously relocating the memory elements. Leiserson and Saxe, who introduced the concept, presented algorithms for period optimization (minperiod retiming) and area optimization (minarea retiming). The ASTRA algorithm proposed an alternative view of retiming using the equivalence between retiming and clock skew optimization;The first part of this thesis defines the relationship between the Leiserson-Saxe and the ASTRA approaches and utilizes it for efficient minarea retiming of large circuits. The new algorithm, Minaret, uses the same linear program formulation as the Leiserson-Saxe approach. The underlying philosophy of the ASTRA approach is incorporated to reduce the number of variables and constraints in this linear program. This allows minarea retiming of circuits with over 56,000 gates in under fifteen minutes;The movement of flip-flops in control logic changes the state encoding of finite state machines, requiring the preservation of initial (reset) states. In the next part of this work the problem of minimizing the number of flip-flops in control logic subject to a specified clock period and with the guarantee of an equivalent initial state, is formulated as a mixed integer linear program. Bounds on the retiming variables are used to guarantee an equivalent initial state in the retimed circuit. These bounds lead to a simple method for calculating an equivalent initial state for the retimed circuit;The transparent nature of level sensitive latches enables level-clocked circuits to operate faster and require less area. However, this transparency makes the operation of level-clocked circuits very complex, and optimization of level-clocked circuits is a difficult task. This thesis also presents efficient algorithms for retiming large level-clocked circuits. The relationship between retiming and clock skew optimization for level-clocked circuits is defined and utilized to develop efficient retiming algorithms for period and area optimization. Using these algorithms a circuit with 56,000 gates could be retimed for minimum period in under twenty seconds and for minimum area in under 1.5 hours

    Exploiting Adaptive Techniques to Improve Processor Energy Efficiency

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    Rapid device-miniaturization keeps on inducing challenges in building energy efficient microprocessors. As the size of the transistors continuously decreasing, more uncertainties emerge in their operations. On the other hand, integrating more and more transistors on a single chip accentuates the need to lower its supply-voltage. This dissertation investigates one of the primary device uncertainties - timing error, in microprocessor performance bottleneck in NTC era. Then it proposes various innovative techniques to exploit these opportunities to maintain processor energy efficiency, in the context of emerging challenges. Evaluated with the cross-layer methodology, the proposed approaches achieve substantial improvements in processor energy efficiency, compared to other start-of-art techniques

    Design methodology and productivity improvement in high speed VLSI circuits

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    2017 Spring.Includes bibliographical references.To view the abstract, please see the full text of the document

    Power efficient and power attacks resistant system design and analysis using aggressive scaling with timing speculation

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    Growing usage of smart and portable electronic devices demands embedded system designers to provide solutions with better performance and reduced power consumption. Due to the new development of IoT and embedded systems usage, not only power and performance of these devices but also security of them is becoming an important design constraint. In this work, a novel aggressive scaling based on timing speculation is proposed to overcome the drawbacks of traditional DVFS and provide security from power analysis attacks at the same time. Dynamic voltage and frequency scaling (DVFS) is proven to be the most suitable technique for power efficiency in processor designs. Due to its promising benefits, the technique is still getting researchers attention to trade off power and performance of modern processor designs. The issues of traditional DVFS are: 1) Due to its pre-calculated operating points, the system is not able to suit to modern process variations. 2) Since Process Voltage and Temperature (PVT) variations are not considered, large timing margins are added to guarantee a safe operation in the presence of variations. The research work presented here addresses these issues by employing aggressive scaling mechanisms to achieve more power savings with increased performance. This approach uses in-situ timing error monitoring and recovering mechanisms to reduce extra timing margins and to account for process variations. A novel timing error detection and correction mechanism, to achieve more power savings or high performance, is presented. This novel technique has also been shown to improve security of processors against differential power analysis attacks technique. Differential power analysis attacks can extract secret information from embedded systems without knowing much details about the internal architecture of the device. Simulated and experimental data show that the novel technique can provide a performance improvement of 24% or power savings of 44% while occupying less area and power overhead. Overall, the proposed aggressive scaling technique provides an improvement in power consumption and performance while increasing the security of processors from power analysis attacks.N/

    Voltage stacking for near/sub-threshold operation

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    Elastic bundles :modelling and architecting asynchronous circuits with granular rigidity

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    PhD ThesisIntegrated Circuit (IC) designs these days are predominantly System-on-Chips (SoCs). The complexity of designing a SoC has increased rapidly over the years due to growing process and environmental variations coupled with global clock distribution di culty. Moreover, traditional synchronous design is not apt to handle the heterogeneous timing nature of modern SoCs. As a countermeasure, the semiconductor industry witnessed a strong revival of asynchronous design principles. A new paradigm of digital circuits emerged, as a result, namely mixed synchronous-asynchronous circuits. With a wave of recent innovations in synchronous-asynchronous CAD integration, this paradigm is showing signs of commercial adoption in future SoCs mainly due to the scope for reuse of synchronous functional blocks and IP cores, and the co-existence of synchronous and asynchronous design styles in a common EDA framework. However, there is a lack of formal methods and tools to facilitate mixed synchronousasynchronous design. In this thesis, we propose a formal model based on Petri nets with step semantics to describe these circuits behaviourally. Implication of this model in the veri cation and synthesis of mixed synchronous-asynchronous circuits is studied. Till date, this paradigm has been mainly explored on the basis of Globally Asynchronous Locally Synchronous (GALS) systems. Despite decades of research, GALS design has failed to gain traction commercially. To understand its drawbacks, a simulation framework characterising the physical and functional aspects of GALS SoCs is presented. A novel method for synthesising mixed synchronous-asynchronous circuits with varying levels of rigidity is proposed. Starting with a high-level data ow model of a system which is intrinsically asynchronous, the key idea is to introduce rigidity of chosen granularity levels in the model without changing functional behaviour. The system is then partitioned into functional blocks of synchronous and asynchronous elements before being transformed into an equivalent circuit which can be synthesised using standard EDA tools

    ์„ฑ๋Šฅ๊ณผ ์šฉ๋Ÿ‰ ํ–ฅ์ƒ์„ ์œ„ํ•œ ์ ์ธตํ˜• ๋ฉ”๋ชจ๋ฆฌ ๊ตฌ์กฐ

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    ํ•™์œ„๋…ผ๋ฌธ (๋ฐ•์‚ฌ)-- ์„œ์šธ๋Œ€ํ•™๊ต ๋Œ€ํ•™์› : ์œตํ•ฉ๊ณผํ•™๊ธฐ์ˆ ๋Œ€ํ•™์› ์œตํ•ฉ๊ณผํ•™๋ถ€(์ง€๋Šฅํ˜•์œตํ•ฉ์‹œ์Šคํ…œ์ „๊ณต), 2019. 2. ์•ˆ์ •ํ˜ธ.The advance of DRAM manufacturing technology slows down, whereas the density and performance needs of DRAM continue to increase. This desire has motivated the industry to explore emerging Non-Volatile Memory (e.g., 3D XPoint) and the high-density DRAM (e.g., Managed DRAM Solution). Since such memory technologies increase the density at the cost of longer latency, lower bandwidth, or both, it is essential to use them with fast memory (e.g., conventional DRAM) to which hot pages are transferred at runtime. Nonetheless, we observe that page transfers to fast memory often block memory channels from servicing memory requests from applications for a long period. This in turn significantly increases the high-percentile response time of latency-sensitive applications. In this thesis, we propose a high-density managed DRAM architecture, dubbed 3D-XPath for applications demanding both low latency and high capacity for memory. 3D-XPath DRAM stacks conventional DRAM dies with high-density DRAM dies explored in this thesis and connects these DRAM dies with 3D-XPath. Especially, 3D-XPath allows unused memory channels to service memory requests from applications when primary channels supposed to handle the memory requests are blocked by page transfers at given moments, considerably increasing the high-percentile response time. This can also improve the throughput of applications frequently copying memory blocks between kernel and user memory spaces. Our evaluation shows that 3D-XPath DRAM decreases high-percentile response time of latency-sensitive applications by โˆผ30% while improving the throughput of an I/O-intensive applications by โˆผ39%, compared with DRAM without 3D-XPath. Recent computer systems are evolving toward the integration of more CPU cores into a single socket, which require higher memory bandwidth and capacity. Increasing the number of channels per socket is a common solution to the bandwidth demand and to better utilize these increased channels, data bus width is reduced and burst length is increased. However, this longer burst length brings increased DRAM access latency. On the memory capacity side, process scaling has been the answer for decades, but cell capacitance now limits how small a cell could be. 3D stacked memory solves this problem by stacking dies on top of other dies. We made a key observation in real multicore machine that multiple memory controllers are always not fully utilized on SPEC CPU 2006 rate benchmark. To bring these idle channels into play, we proposed memory channel sharing architecture to boost peak bandwidth of one memory channel and reduce the burst latency on 3D stacked memory. By channel sharing, the total performance on multi-programmed workloads and multi-threaded workloads improved up to respectively 4.3% and 3.6% and the average read latency reduced up to 8.22% and 10.18%.DRAM ์ œ์กฐ ๊ธฐ์ˆ ์˜ ๋ฐœ์ „์€ ์†๋„๊ฐ€ ๋Š๋ ค์ง€๋Š” ๋ฐ˜๋ฉด DRAM์˜ ๋ฐ€๋„ ๋ฐ ์„ฑ๋Šฅ ์š”๊ตฌ๋Š” ๊ณ„์† ์ฆ๊ฐ€ํ•˜๊ณ  ์žˆ๋‹ค. ์ด๋Ÿฌํ•œ ์š”๊ตฌ๋กœ ์ธํ•ด ์ƒˆ๋กœ์šด ๋น„ ํœ˜๋ฐœ์„ฑ ๋ฉ”๋ชจ๋ฆฌ(์˜ˆ: 3D-XPoint) ๋ฐ ๊ณ ๋ฐ€๋„ DRAM(์˜ˆ: Managed asymmetric latency DRAM Solution)์ด ๋“ฑ์žฅํ•˜์˜€๋‹ค. ์ด๋Ÿฌํ•œ ๊ณ ๋ฐ€๋„ ๋ฉ”๋ชจ๋ฆฌ ๊ธฐ์ˆ ์€ ๊ธด ๋ ˆ์ดํ„ด์‹œ, ๋‚ฎ์€ ๋Œ€์—ญํญ ๋˜๋Š” ๋‘ ๊ฐ€์ง€ ๋ชจ๋‘๋ฅผ ์‚ฌ์šฉํ•˜๋Š” ๋ฐฉ์‹์œผ๋กœ ๋ฐ€๋„๋ฅผ ์ฆ๊ฐ€์‹œํ‚ค๊ธฐ ๋•Œ๋ฌธ์— ์„ฑ๋Šฅ์ด ์ข‹์ง€ ์•Š์•„, ํ•ซ ํŽ˜์ด์ง€๋ฅผ ๊ณ ์† ๋ฉ”๋ชจ๋ฆฌ(์˜ˆ: ์ผ๋ฐ˜ DRAM)๋กœ ์Šค์™‘๋˜๋Š” ์ €์šฉ๋Ÿ‰์˜ ๊ณ ์† ๋ฉ”๋ชจ๋ฆฌ๊ฐ€ ๋™์‹œ์— ์‚ฌ์šฉ๋˜๋Š” ๊ฒƒ์ด ์ผ๋ฐ˜์ ์ด๋‹ค. ์ด๋Ÿฌํ•œ ์Šค์™‘ ๊ณผ์ •์—์„œ ๋น ๋ฅธ ๋ฉ”๋ชจ๋ฆฌ๋กœ์˜ ํŽ˜์ด์ง€ ์ „์†ก์ด ์ผ๋ฐ˜์ ์ธ ์‘์šฉํ”„๋กœ๊ทธ๋žจ์˜ ๋ฉ”๋ชจ๋ฆฌ ์š”์ฒญ์„ ์˜ค๋žซ๋™์•ˆ ์ฒ˜๋ฆฌํ•˜์ง€ ๋ชปํ•˜๋„๋ก ํ•˜๊ธฐ ๋•Œ๋ฌธ์—, ๋Œ€๊ธฐ ์‹œ๊ฐ„์— ๋ฏผ๊ฐํ•œ ์‘์šฉ ํ”„๋กœ๊ทธ๋žจ์˜ ๋ฐฑ๋ถ„์œ„ ์‘๋‹ต ์‹œ๊ฐ„์„ ํฌ๊ฒŒ ์ฆ๊ฐ€์‹œ์ผœ, ์‘๋‹ต ์‹œ๊ฐ„์˜ ํ‘œ์ค€ ํŽธ์ฐจ๋ฅผ ์ฆ๊ฐ€์‹œํ‚จ๋‹ค. ์ด๋Ÿฌํ•œ ๋ฌธ์ œ๋ฅผ ํ•ด๊ฒฐํ•˜๊ธฐ ์œ„ํ•ด ๋ณธ ํ•™์œ„ ๋…ผ๋ฌธ์—์„œ๋Š” ์ € ์ง€์—ฐ์‹œ๊ฐ„ ๋ฐ ๊ณ ์šฉ๋Ÿ‰ ๋ฉ”๋ชจ๋ฆฌ๋ฅผ ์š”๊ตฌํ•˜๋Š” ์• ํ”Œ๋ฆฌ์ผ€์ด์…˜์„ ์œ„ํ•ด 3D-XPath, ์ฆ‰ ๊ณ ๋ฐ€๋„ ๊ด€๋ฆฌ DRAM ์•„ํ‚คํ…์ฒ˜๋ฅผ ์ œ์•ˆํ•œ๋‹ค. ์ด๋Ÿฌํ•œ 3D-ํ†”์†Œ๋ฅผ ์ง‘์ ํ•œ DRAM์€ ์ €์†์˜ ๊ณ ๋ฐ€๋„ DRAM ๋‹ค์ด๋ฅผ ๊ธฐ์กด์˜ ์ผ๋ฐ˜์ ์ธ DRAM ๋‹ค์ด์™€ ๋™์‹œ์— ํ•œ ์นฉ์— ์ ์ธตํ•˜๊ณ , DRAM ๋‹ค์ด๋ผ๋ฆฌ๋Š” ์ œ์•ˆํ•˜๋Š” 3D-XPath ํ•˜๋“œ์›จ์–ด๋ฅผ ํ†ตํ•ด ์—ฐ๊ฒฐ๋œ๋‹ค. ์ด๋Ÿฌํ•œ 3D-XPath๋Š” ํ•ซ ํŽ˜์ด์ง€ ์Šค์™‘์ด ์ผ์–ด๋‚˜๋Š” ๋™์•ˆ ์‘์šฉํ”„๋กœ๊ทธ๋žจ์˜ ๋ฉ”๋ชจ๋ฆฌ ์š”์ฒญ์„ ์ฐจ๋‹จํ•˜์ง€ ์•Š๊ณ  ์‚ฌ์šฉ๋Ÿ‰์ด ์ ์€ ๋ฉ”๋ชจ๋ฆฌ ์ฑ„๋„๋กœ ํ•ซ ํŽ˜์ด์ง€ ์Šค์™‘์„ ์ฒ˜๋ฆฌ ํ•  ์ˆ˜ ์žˆ๋„๋ก ํ•˜์—ฌ, ๋ฐ์ดํ„ฐ ์ง‘์ค‘ ์‘์šฉ ํ”„๋กœ๊ทธ๋žจ์˜ ๋ฐฑ๋ถ„์œ„ ์‘๋‹ต ์‹œ๊ฐ„์„ ๊ฐœ์„ ์‹œํ‚จ๋‹ค. ๋˜ํ•œ ์ œ์•ˆํ•˜๋Š” ํ•˜๋“œ์›จ์–ด ๊ตฌ์กฐ๋ฅผ ์‚ฌ์šฉํ•˜์—ฌ, ์ถ”๊ฐ€์ ์œผ๋กœ O/S ์ปค๋„๊ณผ ์œ ์ € ์ŠคํŽ˜์ด์Šค ๊ฐ„์˜ ๋ฉ”๋ชจ๋ฆฌ ๋ธ”๋ก์„ ์ž์ฃผ ๋ณต์‚ฌํ•˜๋Š” ์‘์šฉ ํ”„๋กœ๊ทธ๋žจ์˜ ์ฒ˜๋ฆฌ๋Ÿ‰์„ ํ–ฅ์ƒ์‹œํ‚ฌ ์ˆ˜ ์žˆ๋‹ค. ์ด๋Ÿฌํ•œ 3D-XPath DRAM์€ 3D-XPath๊ฐ€ ์—†๋Š” DRAM์— ๋น„ํ•ด I/O ์ง‘์•ฝ์ ์ธ ์‘์šฉํ”„๋กœ๊ทธ๋žจ์˜ ์ฒ˜๋ฆฌ๋Ÿ‰์„ ์ตœ๋Œ€ 39 % ํ–ฅ์ƒ์‹œํ‚ค๋ฉด์„œ ๋ ˆ์ดํ„ด์‹œ์— ๋ฏผ๊ฐํ•œ ์‘์šฉ ํ”„๋กœ๊ทธ๋žจ์˜ ๋†’์€ ๋ฐฑ๋ถ„์œ„ ์‘๋‹ต ์‹œ๊ฐ„์„ ์ตœ๋Œ€ 30 %๊นŒ์ง€ ๊ฐ์†Œ์‹œํ‚ฌ ์ˆ˜ ์žˆ๋‹ค. ๋˜ํ•œ ์ตœ๊ทผ์˜ ์ปดํ“จํ„ฐ ์‹œ์Šคํ…œ์€ ๋ณด๋‹ค ๋งŽ์€ ๋ฉ”๋ชจ๋ฆฌ ๋Œ€์—ญํญ๊ณผ ์šฉ๋Ÿ‰์„ ํ•„์š”๋กœํ•˜๋Š” ๋” ๋งŽ์€ CPU ์ฝ”์–ด๋ฅผ ๋‹จ์ผ ์†Œ์ผ“์œผ๋กœ ํ†ตํ•ฉํ•˜๋Š” ๋ฐฉํ–ฅ์œผ๋กœ ์ง„ํ™”ํ•˜๊ณ  ์žˆ๋‹ค. ์ด๋Ÿฌํ•œ ์†Œ์ผ“ ๋‹น ์ฑ„๋„ ์ˆ˜๋ฅผ ๋Š˜๋ฆฌ๋Š” ๊ฒƒ์€ ๋Œ€์—ญํญ ์š”๊ตฌ์— ๋Œ€ํ•œ ์ผ๋ฐ˜์ ์ธ ํ•ด๊ฒฐ์ฑ…์ด๋ฉฐ, ์ตœ์‹ ์˜ DRAM ์ธํ„ฐํŽ˜์ด์Šค์˜ ๋ฐœ์ „ ์–‘์ƒ์€ ์ฆ๊ฐ€ํ•œ ์ฑ„๋„์„ ๋ณด๋‹ค ์ž˜ ํ™œ์šฉํ•˜๊ธฐ ์œ„ํ•ด ๋ฐ์ดํ„ฐ ๋ฒ„์Šค ํญ์ด ๊ฐ์†Œ๋˜๊ณ  ๋ฒ„์ŠคํŠธ ๊ธธ์ด๊ฐ€ ์ฆ๊ฐ€ํ•œ๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ๊ธธ์–ด์ง„ ๋ฒ„์ŠคํŠธ ๊ธธ์ด๋Š” DRAM ์•ก์„ธ์Šค ๋Œ€๊ธฐ ์‹œ๊ฐ„์„ ์ฆ๊ฐ€์‹œํ‚จ๋‹ค. ์ถ”๊ฐ€์ ์œผ๋กœ ์ตœ์‹ ์˜ ์‘์šฉํ”„๋กœ๊ทธ๋žจ์€ ๋” ๋งŽ์€ ๋ฉ”๋ชจ๋ฆฌ ์šฉ๋Ÿ‰์„ ์š”๊ตฌํ•˜๋ฉฐ, ๋ฏธ์„ธ ๊ณต์ •์œผ๋กœ ๋ฉ”๋ชจ๋ฆฌ ์šฉ๋Ÿ‰์„ ์ฆ๊ฐ€์‹œํ‚ค๋Š” ๋ฐฉ๋ฒ•๋ก ์€ ์ˆ˜์‹ญ ๋…„ ๋™์•ˆ ์‚ฌ์šฉ๋˜์—ˆ์ง€๋งŒ, 20 nm ์ดํ•˜์˜ ๋ฏธ์„ธ๊ณต์ •์—์„œ๋Š” ๋” ์ด์ƒ ๊ณต์ • ๋ฏธ์„ธํ™”๋ฅผ ํ†ตํ•ด ๋ฉ”๋ชจ๋ฆฌ ๋ฐ€๋„๋ฅผ ์ฆ๊ฐ€์‹œํ‚ค๊ธฐ๊ฐ€ ์–ด๋ ค์šด ์ƒํ™ฉ์ด๋ฉฐ, ์ ์ธตํ˜• ๋ฉ”๋ชจ๋ฆฌ๋ฅผ ์‚ฌ์šฉํ•˜์—ฌ ์šฉ๋Ÿ‰์„ ์ฆ๊ฐ€์‹œํ‚ค๋Š” ๋ฐฉ๋ฒ•์„ ์‚ฌ์šฉํ•œ๋‹ค. ์ด๋Ÿฌํ•œ ์ƒํ™ฉ์—์„œ, ์‹ค์ œ ์ตœ์‹ ์˜ ๋ฉ€ํ‹ฐ์ฝ”์–ด ๋จธ์‹ ์—์„œ SPEC CPU 2006 ์‘์šฉํ”„๋กœ๊ทธ๋žจ์„ ๋ฉ€ํ‹ฐ์ฝ”์–ด์—์„œ ์‹คํ–‰ํ•˜์˜€์„ ๋•Œ, ํ•ญ์ƒ ์‹œ์Šคํ…œ์˜ ๋ชจ๋“  ๋ฉ”๋ชจ๋ฆฌ ์ปจํŠธ๋กค๋Ÿฌ๊ฐ€ ์™„์ „ํžˆ ํ™œ์šฉ๋˜์ง€ ์•Š๋Š”๋‹ค๋Š” ์‚ฌ์‹ค์„ ๊ด€์ฐฐํ–ˆ๋‹ค. ์ด๋Ÿฌํ•œ ์œ ํœด ์ฑ„๋„์„ ์‚ฌ์šฉํ•˜๊ธฐ ์œ„ํ•ด ํ•˜๋‚˜์˜ ๋ฉ”๋ชจ๋ฆฌ ์ฑ„๋„์˜ ํ”ผํฌ ๋Œ€์—ญํญ์„ ๋†’์ด๊ณ  3D ์Šคํƒ ๋ฉ”๋ชจ๋ฆฌ์˜ ๋ฒ„์ŠคํŠธ ๋Œ€๊ธฐ ์‹œ๊ฐ„์„ ์ค„์ด๊ธฐ ์œ„ํ•ด ๋ณธ ํ•™์œ„ ๋…ผ๋ฌธ์—์„œ๋Š” ๋ฉ”๋ชจ๋ฆฌ ์ฑ„๋„ ๊ณต์œ  ์•„ํ‚คํ…์ฒ˜๋ฅผ ์ œ์•ˆํ•˜์˜€์œผ๋ฉฐ, ํ•˜๋“œ์›จ์–ด ๋ธ”๋ก์„ ์ œ์•ˆํ•˜์˜€๋‹ค. ์ด๋Ÿฌํ•œ ์ฑ„๋„ ๊ณต์œ ๋ฅผ ํ†ตํ•ด ๋ฉ€ํ‹ฐ ํ”„๋กœ๊ทธ๋žจ ๋œ ์‘์šฉํ”„๋กœ๊ทธ๋žจ ๋ฐ ๋‹ค์ค‘ ์Šค๋ ˆ๋“œ ์‘์šฉํ”„๋กœ๊ทธ๋žจ ์„ฑ๋Šฅ์ด ๊ฐ๊ฐ 4.3 % ๋ฐ 3.6 %๋กœ ํ–ฅ์ƒ๋˜์—ˆ์œผ๋ฉฐ ํ‰๊ท  ์ฝ๊ธฐ ๋Œ€๊ธฐ ์‹œ๊ฐ„์€ 8.22 % ๋ฐ 10.18 %๋กœ ๊ฐ์†Œํ•˜์˜€๋‹ค.Contents Abstract i Contents iv List of Figures vi List of Tables viii Introduction 1 1.1 3D-XPath: High-Density Managed DRAM Architecture with Cost-effective Alternative Paths for Memory Transactions 5 1.2 Boosting Bandwidth โ€“ Dynamic Channel Sharing on 3D Stacked Memory 9 1.3 Research contribution 13 1.4 Outline 14 3D-stacked Heterogeneous Memory Architecture with Cost-effective Extra Block Transfer Paths 17 2.1 Background 17 2.1.1 Heterogeneous Main Memory Systems 17 2.1.2 Specialized DRAM 19 2.1.3 3D-stacked Memory 22 2.2 HIGH-DENSITY DRAM ARCHITECTURE 27 2.2.1 Key Design Challenges 29 2.2.2 Plausible High-density DRAM Designs 33 2.3 3D-STACKED DRAM WITH ALTERNATIVE PATHS FOR MEMORY TRANSACTIONS 37 2.3.1 3D-XPath Architecture 41 2.3.2 3D-XPath Management 46 2.4 EXPERIMENTAL METHODOLOGY 52 2.5 EVALUATION 56 2.5.1 OLDI Workloads 56 2.5.2 Non-OLDI Workloads 61 2.5.3 Sensitivity Analysis 66 2.6 RELATED WORK 70 Boosting bandwidth โ€“Dynamic Channel Sharing on 3D Stacked Memory 72 3.1 Background: Memory Operations 72 3.1.1. Memory Controller 72 3.1.2 DRAM column access sequence 73 3.2 Related Work 74 3.3. CHANNEL SHARING ENABLED MEMORY SYSTEM 76 3.3.1 Hardware Requirements 78 3.3.2 Operation Sequence 81 3.4 Analysis 87 3.4.1 Experiment Environment 87 3.4.2 Performance 88 3.4.3 Overhead 90 CONCLUSION 92 REFERENCES 94 ๊ตญ๋ฌธ์ดˆ๋ก 107Docto
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