Making Speculative Scheduling Robust to Incomplete Data

International audienceIn this work, we study the robustness of SpeculativeScheduling to data incompleteness. Speculative scheduling hasallowed to incorporate future types of applications into thedesign of HPC schedulers, specifically applications whose runtimeis not perfectly known but can be modeled with probabilitydistributions. Preliminary studies show the importance of spec-ulative scheduling in dealing with stochastic applications whenthe application runtime model is completely known. In this workwe show how one can extract enough information even fromincomplete behavioral data for a given HPC applications sothat speculative scheduling still performs well. Specifically, weshow that for synthetic runtimes who follow usual probabilitydistributions such as truncated normal or exponential, we canextract enough data from as little as 10 previous runs, to bewithin 5% of the solution which has exact information. For realtraces of applications, the performance with 10 data points varieswith the applications (within 20% of the full-knowledge solution),but converges fast (5% with 100 previous samples).Finally a side effect of this study is to show the importanceof the theoretical results obtained on continuous probabilitydistributions for speculative scheduling. Indeed, we observe thatthe solutions for such distributions are more robust to incompletedata than the solutions for discrete distributions

Identifying Data Exchange Congestion Through Real-Time Monitoring Of Beowulf Cluster Infiniband Networks

The ability to gather data from many types of new information sources has grown quickly using new technologies. The ability to store and retrieve large quantities of data from these new sources has created a need for computing platforms that are able to process the data for information. High Performance Computing Cluster systems have been developed to fulfill a role required for fast processing of large amounts of data for many difficult types of computing applications. Beowulf Clusters use many separate compute nodes to create a tightly coupled parallel HPCC system. The ability for a Beowulf Cluster HPCC system to process data depends on the ability of the compute nodes within the HPCC system to be able to retrieve data, share data, and store data with as little delay as possible. With many compute nodes competing to exchange data over limited network connections, network congestion can occur that can negatively impact the speed of computations. With concerns about network performance optimization, and uneven distribution of computational capacity, it is important for Beowulf HPCC System Administrators to be able to evaluate real-time data transfer metrics for congestion within a particular HPCC system. In this thesis, Heat-Maps will be created to identify potential issues with Infiniband network congestion due to simultaneous data exchanges between compute nodes

MAGNETIC: Multi-Agent Machine Learning-Based Approach for Energy Efficient Dynamic Consolidation in Data Centers

Improving the energy efficiency of data centers while guaranteeing Quality of Service (QoS), together with detecting performance variability of servers caused by either hardware or software failures, are two of the major challenges for efficient resource management of large-scale cloud infrastructures. Previous works in the area of dynamic Virtual Machine (VM) consolidation are mostly focused on addressing the energy challenge, but fall short in proposing comprehensive, scalable, and low-overhead approaches that jointly tackle energy efficiency and performance variability. Moreover, they usually assume over-simplistic power models, and fail to accurately consider all the delay and power costs associated with VM migration and host power mode transition. These assumptions are no longer valid in modern servers executing heterogeneous workloads and lead to unrealistic or inefficient results. In this paper, we propose a centralized-distributed low-overhead failure-aware dynamic VM consolidation strategy to minimize energy consumption in large-scale data centers. Our approach selects the most adequate power mode and frequency of each host during runtime using a distributed multi-agent Machine Learning (ML) based strategy, and migrates the VMs accordingly using a centralized heuristic. Our Multi-AGent machine learNing-based approach for Energy efficienT dynamIc Consolidation (MAGNETIC) is implemented in a modified version of the CloudSim simulator, and considers the energy and delay overheads associated with host power mode transition and VM migration, and is evaluated using power traces collected from various workloads running in real servers and resource utilization logs from cloud data center infrastructures. Results show how our strategy reduces data center energy consumption by up to 15% compared to other works in the state-of-the-art (SoA), guaranteeing the same QoS and reducing the number of VM migrations and host power mode transitions by up to 86% and 90%, respectively. Moreover, it shows better scalability than all other approaches, taking less than 0.7% time overhead to execute for a data center with 1500 VMs. Finally, our solution is capable of detecting host performance variability due to failures, automatically migrating VMs from failing hosts and draining them from workload

Improving efficiency and resilience in large-scale computing systems through analytics and data-driven management

Applications running in large-scale computing systems such as high performance computing (HPC) or cloud data centers are essential to many aspects of modern society, from weather forecasting to financial services. As the number and size of data centers increase with the growing computing demand, scalable and efficient management becomes crucial. However, data center management is a challenging task due to the complex interactions between applications, middleware, and hardware layers such as processors, network, and cooling units. This thesis claims that to improve robustness and efficiency of large-scale computing systems, significantly higher levels of automated support than what is available in today's systems are needed, and this automation should leverage the data continuously collected from various system layers. Towards this claim, we propose novel methodologies to automatically diagnose the root causes of performance and configuration problems and to improve efficiency through data-driven system management. We first propose a framework to diagnose software and hardware anomalies that cause undesired performance variations in large-scale computing systems. We show that by training machine learning models on resource usage and performance data collected from servers, our approach successfully diagnoses 98% of the injected anomalies at runtime in real-world HPC clusters with negligible computational overhead. We then introduce an analytics framework to address another major source of performance anomalies in cloud data centers: software misconfigurations. Our framework discovers and extracts configuration information from cloud instances such as containers or virtual machines. This is the first framework to provide comprehensive visibility into software configurations in multi-tenant cloud platforms, enabling systematic analysis for validating the correctness of software configurations. This thesis also contributes to the design of robust and efficient system management methods that leverage continuously monitored resource usage data. To improve performance under power constraints, we propose a workload- and cooling-aware power budgeting algorithm that distributes the available power among servers and cooling units in a data center, achieving up to 21% improvement in throughput per Watt compared to the state-of-the-art. Additionally, we design a network- and communication-aware HPC workload placement policy that reduces communication overhead by up to 30% in terms of hop-bytes compared to existing policies.2019-07-02T00:00:00