Energy - and Heat-aware HPC Benchmarks

International audienceTo evaluate data centers is tough. Several metrics are available to provide insight into their behaviour, but usually they are tested using simple benchmarks like LINPACK for HPC oriented data centers. A good choice of benchmarks is necessary to evaluate all the impact of applications on those data centers. One point that is often overlooked is their energy- and thermal-quality. To evaluate these qualities, adequate benchmarks are required from several points of view: from the nodes to the whole building. Classical benchmarks selection mainly focuses on time and raw performance. This article aims at shifting the focus towards an energy- and power-point of view. To this end, we select benchmarks able to evaluate data centers not only from this performance perspective, but also from the energy and thermal standpoint. We also provide insight into several classical benchmarks and method to select an adequate and small number of benchmarks in order to provide a sensible and minimum set of energy- and thermal-aware benchmarks for HPC systems

Energy-efficient Assignment of Applications to Servers by Taking into Account the Influence of Processes on Each Other

Proceedings of: Third International Workshop on Sustainable Ultrascale Computing Systems (NESUS 2016). Sofia (Bulgaria), October, 6-7, 2016.The power consumption of data centers is becoming a crucial challenge in the context of the steadily increasing demand for computation. In this regard finding a way to improve energy efficiency of running applications in data centers is becoming a crucial trend. One method to improve the processor utilization is the consolidation of applications on physical servers. It is possible to run multiple jobs in parallel on the same machine, especially when their requirements regarding computation are smaller than the maximum processor performance. It reduces the number of servers in the data center required to handle multiple requests and therefore leads to energy usage reductions. In this paper, we introduce a realistic model of applications with deadlines executed in parallel on a server and competing for the shared resources and present an energy-aware algorithm which may be used to minimize the overall energy consumption of the servers.European Community's Seventh Framework ProgramThis work is partially supported by EU under the COST Program Action 1305: Network for Sustainable Ultrascale Computing (NESUS). The research presented in this paper is partially funded by a grant from Polish National Science Center under award number 2013/08/A/ST6/00296. This research was supported by the EU Seventh Framework Programme FP7/2007–2013 under grant agreement no. FP7-ICT-2013-10 (609757)

Modeling Data Center Building Blocks for Energy-efficiency and Thermal Simulations

International audienceIn this paper we present a concept and specification of Data Center Efficiency Building Blocks (DEBBs), which represent hardware components of a data center complemented by descriptions of their energy efficiency. Proposed building blocks contain hardware and thermodynamic models that can be applied to simulate a data center and to evaluate its energy efficiency. DEBBs are available in an open repository being built by the CoolEmAll project. In the paper we illustrate the concept by an example of DEBB defined for the RECS multi-server system including models of its power usage and thermodynamic properties. We also show how these models are affected by specific architecture of modeled hardware and differences between various classes of applications. Proposed models are verified by a comparison to measurements on a real infrastructure. Finally, we demonstrate how DEBBs are used in data center simulations

Is narrow-band imaging a useful tool in screening colonoscopy performed by an experienced endoscopist? : a prospective randomised study on 533 patients

Introduction: The detection of adenomas is the basic goal for colorectal cancer screening programs; therefore, every possibility to improve the adenoma detection rate is valuable. Aim: To answer the question of whether narrow-band imaging (NBI) can enhance detection quality in screening for colonoscopy. Material and methods: A group of 533 patients (202 men: 331 women; average age: 56.1 years) included in a colorectal cancer screening program were randomised into two groups (NBI n = 266 and white light (WL) n = 267). Five hundred and twentyseven patients were finally included in the assessment. Examinations were performed by three experienced colonoscopists. The NBI was used only at the withdrawal of the instrument. Results: Comparing WL and NBI colonoscopies, differences in the mean number of detected polyps per patient (1.36 ±2.79 WL vs. 1.65 ±2.11 NBI; p = 0.012), polyp detection rate (PDR) (48.5% WL vs. 57.2% NBI; p = 0.049), PDR for polyps ≤ 5 mm (44.7% WL vs. 54% NBI; p = 0.033), and PDR for left-sided polyps (43.3% WL vs. 52.7% NBI; p = 0.033) were observed. The difference in adenoma detection rate (ADR) as well as in adenomas/patient was not significant. Narrow-band imaging enhanced significantly one of three operators’ ADR (15.6% WL vs. 25.7% NBI; p = 0.038). Conclusions: It seems that NBI improves only detection of hyperplastic polyps, especially those that are diminutive and left-sided. However, after analysis of particular endoscopists, it can clearly be seen that some of them may benefit from NBI

CoolEmAll: Models and Tools for Planning and Operating Energy Efficient Data Centres

International audienceThe need to improve how efficiently data centre operate is increasing due to the continued high demand for new data centre capacity combined with other factors such as the increased competition for energy resources. The financial crisis may have dampened data centre demand temporarily, but current projections indicate strong growth ahead. By 2020, it is estimated that annual investment in the construction of new data centres will rise to \ 50bn in the US, and \ 220bn worldwid