CloudScope: diagnosing and managing performance interference in multi-tenant clouds

© 2015 IEEE.Virtual machine consolidation is attractive in cloud computing platforms for several reasons including reduced infrastructure costs, lower energy consumption and ease of management. However, the interference between co-resident workloads caused by virtualization can violate the service level objectives (SLOs) that the cloud platform guarantees. Existing solutions to minimize interference between virtual machines (VMs) are mostly based on comprehensive micro-benchmarks or online training which makes them computationally intensive. In this paper, we present CloudScope, a system for diagnosing interference for multi-tenant cloud systems in a lightweight way. CloudScope employs a discrete-time Markov Chain model for the online prediction of performance interference of co-resident VMs. It uses the results to optimally (re)assign VMs to physical machines and to optimize the hypervisor configuration, e.g. the CPU share it can use, for different workloads. We have implemented CloudScope on top of the Xen hypervisor and conducted experiments using a set of CPU, disk, and network intensive workloads and a real system (MapReduce). Our results show that CloudScope interference prediction achieves an average error of 9%. The interference-aware scheduler improves VM performance by up to 10% compared to the default scheduler. In addition, the hypervisor reconfiguration can improve network throughput by up to 30%

Outlook and appraisal [November 2004]

Strong growth in the second quarter suggests that the Scottish economy has recovered from the doldrums of the previous three quarters. A rebound in service sector performance was the main reason. Manufacturing remains weak, although the sector has exhibited some positive growth over the last three quarters. Electronics production continues to contract in Scotland, whereas this is not the case in the UK as a whole. Financial and business services are leading the recovery in Scottish services, supported by retail and hotels and catering. Analysis of Scotland's GDP per head performance during the 1990s and the first two years of the current decade, highlights Scotland's relatively weaker productivity performance when compared to the UK. But Scotland also appears to have enjoyed a better labour market performance with a rising employment rate and movement of the population into the labour force contributing more to the growth of GDP per head than in the UK. This analysis highlights the productivity challenge facing Scotland. But it also emphasises the importance of migration and population enhancing policies to prevent a declining population from eroding many of the opportunities for future GDP per head growth

On the conditions for efficient interoperability with threads: An experience with PGAS languages using Cray communication domains

Today's high performance systems are typically built from shared memory nodes connected by a high speed network. That architecture, combined with the trend towards less memory per core, encourages programmers to use a mixture of message passing and multithreaded programming. Unfortunately, the advantages of using threads for in-node programming are hindered by their inability to efficiently communicate between nodes. In this work, we identify some of the performance problems that arise in such hybrid programming environments and characterize conditions needed to achieve high communication performance for multiple threads: addressability of targets, separability of communication paths, and full direct reachability to targets. Using the GASNet communication layer on the Cray XC30 as our experimental platform, we show how to satisfy these conditions. We also discuss how satisfying these conditions is influenced by the communication abstraction, implementation constraints, and the interconnect messaging capabilities. To evaluate these ideas, we compare the communication performance of a thread-based node runtime to a process-based runtime. Without our GASNet extensions, thread communication is significantly slower than processes - up to 21x slower. Once the implementation is modified to address each of our conditions, the two runtimes have comparable communication performance. This allows programmers to more easily mix models like OpenMP, CILK, or pthreads with a GASNet-based model like UPC, with the associated performance, convenience and interoperability advantages that come from using threads within a node. © 2014 ACM

What Turkey expects from logistics outsourcing ?

Copyright @ 2011 Yasar UniversityThe economies of the world have become increasingly interdependent, and organizations have come under tremendous pressure to maximize productivity and profitability. Creating value through outsourcing has emerged as a popular competitive strategy for firms of all sizes in all types of industries. The aim of this research is to investigate the use of third party logistics in Turkish companies from the users’ perspective to identify the types of logistics services outsourced, problems encountered in outsourcing these services, logistics costs, decision makers in outsourcing logistics activities, and information sources used in the decision-making process. A structured survey was selected as the tool for data collection. The field study involved face-to-face interviews with 204 companies out of top 500 companies ranked in terms of turnover that are registered with industrial associations and chambers of commerce in Turkey. Moreover, a decision support system based on Bayesian Causal Map is proposed for 3PLs in order to assist them in their service proposals for different sectors. This study is a first attempt to reveal and compare the outsourcing perception of the companies in different sectors, to expose the firms’ underlying motives as well as the respective importance of these motives for outsourcing logistics activities in Turkey. The use of Bayesian Causal Map based on the survey results provides an important guide to the 3PL providers to pick a suitable strategy and to prioritize their operational activities in different sectors in such a way to achieve a competitive advantage

SoS in Disasters: Why following the manual can be a mistake

According to both the US Geological Survey and the World Bank, $280 billion dollars could have been saved if$40 billion dollars had been invested in disaster prevention. Natural and human-made disasters that have occurred over the last few years show that there is a gap in disaster prevention caused by the interconnected nature of risks, which cannot be foreseen with current risk management methods. In this paper we point out how disaster management could benefit from a SoS approach in emergency response and preparedness strategies. Using recent disasters as case studies, we identify some keys to success in managing a SoS in preparation, during and in the aftermath of a disaster. In particular, we discuss the idea of the interconnectedness of risks in independent and interdependent systems and the application of Boardman and Sauser’s concept of “creative disobedience”, which are fundamental for goal achievement of systems belonging to a SoS

AFRICA'S UNFINISHED BUSINESS: BUILDING SUSTAINABLE AGRICULTURAL RESEARCH SYSTEMS

This paper addresses four questions: · What lessons can be drawn from the "rise and decline" of NARS in Africa? · What can African research managers learn from some of the successful reforms of NARS in Asia and Latin America over the past 10 to 15 years? · What are the major challenges facing the NARS in the ASARECA region in the coming 10-20 years? · What are the critical reforms and the incentives needed to develop pluralistic, accountable, productive and financially self-sustaining NARS in AFRICA?Research and Development/Tech Change/Emerging Technologies,

Taking stock of structural funds implementation : current challenges and future opportunities

This paper highlights several themes which have informed programme management since IQ-Net meeting in June 2002, held in Lulea, Sweden. First, it provides an overview of the main development in programme implementation and the financial execution of programmes, including an exploration of the risks of automatic decommitment faced by the programmes. Second, it describes the progress made with the mid-term evaluations, following on the IQ-Net thematic paper on this subject presented at the Lulea conference. Third, it presents an overview of the current EU-level debate on simplification, highlighting the views of the network's partners as well as, where available, the member state