4,117 research outputs found

    TANDEM: taming failures in next-generation datacenters with emerging memory

    Get PDF
    The explosive growth of online services, leading to unforeseen scales, has made modern datacenters highly prone to failures. Taming these failures hinges on fast and correct recovery, minimizing service interruptions. Applications, owing to recovery, entail additional measures to maintain a recoverable state of data and computation logic during their failure-free execution. However, these precautionary measures have severe implications on performance, correctness, and programmability, making recovery incredibly challenging to realize in practice. Emerging memory, particularly non-volatile memory (NVM) and disaggregated memory (DM), offers a promising opportunity to achieve fast recovery with maximum performance. However, incorporating these technologies into datacenter architecture presents significant challenges; Their distinct architectural attributes, differing significantly from traditional memory devices, introduce new semantic challenges for implementing recovery, complicating correctness and programmability. Can emerging memory enable fast, performant, and correct recovery in the datacenter? This thesis aims to answer this question while addressing the associated challenges. When architecting datacenters with emerging memory, system architects face four key challenges: (1) how to guarantee correct semantics; (2) how to efficiently enforce correctness with optimal performance; (3) how to validate end-to-end correctness including recovery; and (4) how to preserve programmer productivity (Programmability). This thesis aims to address these challenges through the following approaches: (a) defining precise consistency models that formally specify correct end-to-end semantics in the presence of failures (consistency models also play a crucial role in programmability); (b) developing new low-level mechanisms to efficiently enforce the prescribed models given the capabilities of emerging memory; and (c) creating robust testing frameworks to validate end-to-end correctness and recovery. We start our exploration with non-volatile memory (NVM), which offers fast persistence capabilities directly accessible through the processor’s load-store (memory) interface. Notably, these capabilities can be leveraged to enable fast recovery for Log-Free Data Structures (LFDs) while maximizing performance. However, due to the complexity of modern cache hierarchies, data hardly persist in any specific order, jeop- ardizing recovery and correctness. Therefore, recovery needs primitives that explicitly control the order of updates to NVM (known as persistency models). We outline the precise specification of a novel persistency model – Release Persistency (RP) – that provides a consistency guarantee for LFDs on what remains in non-volatile memory upon failure. To efficiently enforce RP, we propose a novel microarchitecture mechanism, lazy release persistence (LRP). Using standard LFDs benchmarks, we show that LRP achieves fast recovery while incurring minimal overhead on performance. We continue our discussion with memory disaggregation which decouples memory from traditional monolithic servers, offering a promising pathway for achieving very high availability in replicated in-memory data stores. Achieving such availability hinges on transaction protocols that can efficiently handle recovery in this setting, where compute and memory are independent. However, there is a challenge: disaggregated memory (DM) fails to work with RPC-style protocols, mandating one-sided transaction protocols. Exacerbating the problem, one-sided transactions expose critical low-level ordering to architects, posing a threat to correctness. We present a highly available transaction protocol, Pandora, that is specifically designed to achieve fast recovery in disaggregated key-value stores (DKVSes). Pandora is the first one-sided transactional protocol that ensures correct, non-blocking, and fast recovery in DKVS. Our experimental implementation artifacts demonstrate that Pandora achieves fast recovery and high availability while causing minimal disruption to services. Finally, we introduce a novel target litmus-testing framework – DART – to validate the end-to-end correctness of transactional protocols with recovery. Using DART’s target testing capabilities, we have found several critical bugs in Pandora, highlighting the need for robust end-to-end testing methods in the design loop to iteratively fix correctness bugs. Crucially, DART is lightweight and black-box, thereby eliminating any intervention from the programmers

    Inovação na diplomacia cultural: o caso da China

    Get PDF
    This study focuses on the innovation of China’s cultural diplomacy (CCD) by means of the Confucius Institute (CI). The main contents revolve around the following research goals: 1) to understand the strategic framework and practical path of CCD, and to clarify the context of its inheritance and innovation; 2) to analyze whether the CI, epitomized as a crucial innovation of CCD, has improved China’s national image in Portuguese-speaking countries (PSCs) and enhanced the attraction and international competitiveness of Chinese culture; and 3) to explore how China can better formulate its CD strategy in line with the exigencies of the modern era. The study combines the methods of literature review, case study, and questionnaire research to explore the topics from different perspectives to strengthen the scientific nature of the research results. In addition to the introduction and conclusion, the thesis is divided into five chapters. Chapter 1 discusses the connotation and value of CD. Chapter 2 expounds the development and innovation of CCD. Chapter 3 systematically summarizes China’s cultural interaction in its diplomatic process with PSCs. Chapter 4 elaborates on the CI in terms of its operation mode and diplomatic means. Chapter 5 forms the core of the study and involves empirical analysis of case-study and questionnaire data. It aims to investigate the functions, public image, influence, and practical means of CIs in the process of CD. Major findings indicate that CIs in PSCs have achieved ideal social feedback and play a positive role in shaping the image of China. However, according to the different continents where CIs are located, the survey results show distinct characteristics which are closely related to China’s different foreign policies towards Latin America, Europe, and Africa and are determined by the historical experiences and national conditions of the various countries. The future task for CCD is to clarify China’s institutional roots and the cultural genes behind its development by using cultural exchanges and China’s fluid culture to convey a message of China’s pursuit of peace, development, and cooperation.Este estudo tem como foco a inovação da Diplomacia Cultural da China (DCC) através do Instituto Confúcio (IC). Os principais conteúdos giram em torno dos seguintes objetivos de investigação: 1) compreender o enquadramento estratégico e o percurso prático da Diplomacia Cultural da China e clarificar o contexto da sua herança e inovação; 2) analisar se o IC, exemplo de inovação crucial da Diplomacia Cultural da China, melhorou a imagem nacional da China nos Países de Língua Oficial Portuguesa (PALOP) e aumentou a atração e competitividade internacional da cultura chinesa; e 3) explorar como a China pode formular melhor a sua estratégia de Diplomacia Cultural, de acordo com as exigências da era moderna. O estudo combina os métodos de revisão de literatura, estudo de caso e pesquisa de questionário para explorar os tópicos de diferentes perspetivas com o objetivo de fortalecer a natureza científica dos resultados de investigação. Além da introdução e da conclusão, a tese está dividida em cinco capítulos. O Capítulo 1 discute a conotação e o valor de Diplomacia Cultural (DC). O Capítulo 2 expõe o desenvolvimento e a inovação da Diplomacia Cultural da China (DCC). O Capítulo 3 resume sistematicamente a interação cultural da China no seu processo diplomático com os Países de Língua Oficial Portuguesa (PALOP). O Capítulo 4 discorre sobre o papel do IC em termos do seu modo de operar e dos seus meios diplomáticos. O Capítulo 5 constitui o núcleo da tese e envolve a análise empírica dos dados do estudo de caso e do questionário. Tem como objetivo investigar as funções, a imagem pública, a influência e os meios práticos dos IC no processo de Diplomacia Cultural (DC). As principais descobertas indicam que os IC nos PALOP alcançaram o feedback social ideal e desempenham um papel positivo na formação da imagem da China. No entanto, de acordo com os diferentes continentes onde os IC estão situados, os resultados da pesquisa apresentam caraterísticas distintas que estão intimamente relacionadas com as diferentes políticas externas da China para a América Latina, a Europa e a África e são determinadas pelas experiências históricas e pelas condições nacionais dos vários países. A futura tarefa da Diplomacia Cultural da China (DCC) será a de esclarecer as raízes institucionais da China e os genes culturais por trás do seu desenvolvimento, usando intercâmbios culturais e a cultura fluida da China para transmitir uma mensagem de busca de paz, de desenvolvimento e de cooperação por parte da China.Programa Doutoral em Políticas Pública

    Digitalization and Development

    Get PDF
    This book examines the diffusion of digitalization and Industry 4.0 technologies in Malaysia by focusing on the ecosystem critical for its expansion. The chapters examine the digital proliferation in major sectors of agriculture, manufacturing, e-commerce and services, as well as the intermediary organizations essential for the orderly performance of socioeconomic agents. The book incisively reviews policy instruments critical for the effective and orderly development of the embedding organizations, and the regulatory framework needed to quicken the appropriation of socioeconomic synergies from digitalization and Industry 4.0 technologies. It highlights the importance of collaboration between government, academic and industry partners, as well as makes key recommendations on how to encourage adoption of IR4.0 technologies in the short- and long-term. This book bridges the concepts and applications of digitalization and Industry 4.0 and will be a must-read for policy makers seeking to quicken the adoption of its technologies

    Low-Overhead Online Assessment of Timely Progress as a System Commodity

    Get PDF

    A Survey of FPGA Optimization Methods for Data Center Energy Efficiency

    Get PDF
    This article provides a survey of academic literature about field programmable gate array (FPGA) and their utilization for energy efficiency acceleration in data centers. The goal is to critically present the existing FPGA energy optimization techniques and discuss how they can be applied to such systems. To do so, the article explores current energy trends and their projection to the future with particular attention to the requirements set out by the European Code of Conduct for Data Center Energy Efficiency. The article then proposes a complete analysis of over ten years of research in energy optimization techniques, classifying them by purpose, method of application, and impacts on the sources of consumption. Finally, we conclude with the challenges and possible innovations we expect for this sector.Comment: Accepted for publication in IEEE Transactions on Sustainable Computin

    Enabling dynamic and intelligent workflows for HPC, data analytics, and AI convergence

    Get PDF
    The evolution of High-Performance Computing (HPC) platforms enables the design and execution of progressively larger and more complex workflow applications in these systems. The complexity comes not only from the number of elements that compose the workflows but also from the type of computations they perform. While traditional HPC workflows target simulations and modelling of physical phenomena, current needs require in addition data analytics (DA) and artificial intelligence (AI) tasks. However, the development of these workflows is hampered by the lack of proper programming models and environments that support the integration of HPC, DA, and AI, as well as the lack of tools to easily deploy and execute the workflows in HPC systems. To progress in this direction, this paper presents use cases where complex workflows are required and investigates the main issues to be addressed for the HPC/DA/AI convergence. Based on this study, the paper identifies the challenges of a new workflow platform to manage complex workflows. Finally, it proposes a development approach for such a workflow platform addressing these challenges in two directions: first, by defining a software stack that provides the functionalities to manage these complex workflows; and second, by proposing the HPC Workflow as a Service (HPCWaaS) paradigm, which leverages the software stack to facilitate the reusability of complex workflows in federated HPC infrastructures. Proposals presented in this work are subject to study and development as part of the EuroHPC eFlows4HPC project.This work has received funding from the European High-Performance Computing Joint Undertaking (JU) under grant agreement No 955558. The JU receives support from the European Union’s Horizon 2020 research and innovation programme and Spain, Germany, France, Italy, Poland, Switzerland and Norway. In Spain, it has received complementary funding from MCIN/AEI/10.13039/501100011033, Spain and the European Union NextGenerationEU/PRTR (contracts PCI2021-121957, PCI2021-121931, PCI2021-121944, and PCI2021-121927). In Germany, it has received complementary funding from the German Federal Ministry of Education and Research (contracts 16HPC016K, 6GPC016K, 16HPC017 and 16HPC018). In France, it has received financial support from Caisse des dépôts et consignations (CDC) under the action PIA ADEIP (project Calculateurs). In Italy, it has been preliminary approved for complimentary funding by Ministero dello Sviluppo Economico (MiSE) (ref. project prop. 2659). In Norway, it has received complementary funding from the Norwegian Research Council, Norway under project number 323825. In Switzerland, it has been preliminary approved for complimentary funding by the State Secretariat for Education, Research, and Innovation (SERI), Norway. In Poland, it is partially supported by the National Centre for Research and Development under decision DWM/EuroHPCJU/4/2021. The authors also acknowledge financial support by MCIN/AEI /10.13039/501100011033, Spain through the “Severo Ochoa Programme for Centres of Excellence in R&D” under Grant CEX2018-000797-S, the Spanish Government, Spain (contract PID2019-107255 GB) and by Generalitat de Catalunya, Spain (contract 2017-SGR-01414). Anna Queralt is a Serra Húnter Fellow.With funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2018-000797-S)
    corecore