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- Roozbeh, Amir, 1983-
(författare)
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Realizing Next-Generation Data Centers via Software-Defined “Hardware” Infrastructures and Resource Disaggregation : Exploiting your cache
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The cloud is evolving due to additional demands introduced by new technological advancements and the wide movement toward digitalization. Moreover, next-generation Data Centers (DCs) and clouds are expected (and need) to become cheaper, more efficient, and capable of offering more predictable services. Aligned with this, this thesis examines the concept of Software-Defined “Hardware” Infrastructure (SDHI) based on hardware resource disaggregation as one possible way of realizing next-generation DCs. This thesis starts with an overview of the functional architecture of a cloud based on SDHI. Following this, a series of use-cases and deployment scenarios enabled by SDHI are discussed along with an exploration of the role of each functional block of SDHI’s architecture, i.e., cloud infrastructure, cloud platforms, cloud execution environments, and applications.This thesis proposes a framework to evaluate the impact of SDHI on the techno-economic efficiency of DCs, explicitly focusing on application profiling, hardware dimensioning, and Total Cost of Ownership (TCO). It then shows that combining resource disaggregation and software-defined capabilities makes DCs less expensive and easier to expand; hence, they can rapidly follow the expected exponential demand growth. Additionally, this thesis elaborates the technologies underlying SDHI, its challenges, and its potential future directions.It is advocated that achieving and maintaining a high level of memory performance is crucial for realizing SDHI & disaggregated DC. Nevertheless, a memory management and Input/Output (I/O) data management scheme suitable for SDHI is proposed and its advantages are shown. This work focuses on the management of Last Level Cache (LLC) in currently available Intel processors, takes advantage of LLC’s Non-Uniform Cache Architectures (NUCA), and investigates how better utilization of LLC can provide higher performance, more predictable response time, and improved isolation between threads. Additionally, this thesis scrutinizes the impact of cache management, specifically Direct Cache Access (DCA), on the performance of I/O intensive applications. The results of an empirical study shows that the proposed memory management scheme enables system designers and developers to optimize systems for I/O intensive applications and highlights some potential changes expected for I/O management in future DC systems.
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| 2. |
- Stavlöt, Ulrika, 1969-
(författare)
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Essays on Culture and Trade
- 2005
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis consists of three self-contained essays. The first two essays address the consumption of culture and are closely related in terms of the theoretical framework used. The third essay is a separate analysis of international trade and competition.The studies of culture are motivated by the special treatment of culture consumption in most modern societies: there are usually large, government-provided subsidies, the aim of which is to stimulate both the production and the consumption of culture. The purpose of the present work is to explore reasons for this special treatment. Using a stylized theoretical framework, the essays contrast culture with another, generic, good or activity. Culture is thus regarded as an "experience good": previous consumption of the good enhances the current appreciation of the good. The generic good is one where experience is assumed not to be at all relevant for the appreciation of the good. For experience goods, decisions made today will influence future utility and future choices. This makes the intertemporal preferences essential. If, in particular, consumers have time-inconsistent preferences of the type that can be characterized as a present-bias---modeled with "multiple selves" using quasi-geometric discounting---as opposed to standard, time-consistent preferences, there will be a case for government subsidies. The first essay explores this possibility in detail in a framework where experience is mainly of importance in the short run. The second essay then studies cases where experience is more potent and can cause persistent diversity in culture consumption across individuals."Culture and Control: Should There Be Large Subsidies to Culture?" studies the circumstances under which public support for culture is warranted. A policy example is designed to illustrate important aspects of public support systems currently in place, and is calibrated to Swedish data. The essay concludes that, given present-biased agents with self-control problems, public support of culture can work as a commitment device and improve long-run welfare. Furthermore, it is demonstrated that welfare-maximizing subsidies to culture can be substantial if the present-bias is profound and the taste-cultivation property of culture consumption is pronounced."Origins of the Diversity of Culture Consumption" analyzes the diversity of culture consumption among individuals. If the culture good and the generic good are sufficiently close substitutes in a static sense, very large and persistent differences in the consumption of highbrow culture across consumers can be explained by differences in initial experience levels alone. Moreover, slight differences in preferences and time endowments can cause significant diversity between individuals, both in the long- and short-run levels of culture consumption. In addition, if consumers have time-inconsistent preferences, further diversity can be rationalized. If there is a present-bias, there may also be Pareto-ranked multiple equilibria with "optimism" and "pessimism": high (low) culture consumption of the current self is rationalized, based on the belief that future culture consumption will be high (low)."Has international competition increased? Estimates of residual demand elasticities in export markets" studies the impact of the last decades of intense economic integration on the competitive conduct of Swedish export industries. The functional relationship between the inverted residual demand elasticity and the Lerner index is used to estimate markups in eight industries. The econometric evidence suggests a deviation from competitive behavior in all industries. Moreover, the results demonstrate a trend of decreasing market power.
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