2,138 research outputs found
Scheduling for a Processor Sharing System with Linear Slowdown
We consider the problem of scheduling arrivals to a congestion system with a
finite number of users having identical deterministic demand sizes. The
congestion is of the processor sharing type in the sense that all users in the
system at any given time are served simultaneously. However, in contrast to
classical processor sharing congestion models, the processing slowdown is
proportional to the number of users in the system at any time. That is, the
rate of service experienced by all users is linearly decreasing with the number
of users. For each user there is an ideal departure time (due date). A
centralized scheduling goal is then to select arrival times so as to minimize
the total penalty due to deviations from ideal times weighted with sojourn
times. Each deviation is assumed quadratic, or more generally convex. But due
to the dynamics of the system, the scheduling objective function is non-convex.
Specifically, the system objective function is a non-smooth piecewise convex
function. Nevertheless, we are able to leverage the structure of the problem to
derive an algorithm that finds the global optimum in a (large but) finite
number of steps, each involving the solution of a constrained convex program.
Further, we put forward several heuristics. The first is the traversal of
neighbouring constrained convex programming problems, that is guaranteed to
reach a local minimum of the centralized problem. This is a form of a "local
search", where we use the problem structure in a novel manner. The second is a
one-coordinate "global search", used in coordinate pivot iteration. We then
merge these two heuristics into a unified "local-global" heuristic, and
numerically illustrate the effectiveness of this heuristic
Metascheduling of HPC Jobs in Day-Ahead Electricity Markets
High performance grid computing is a key enabler of large scale collaborative
computational science. With the promise of exascale computing, high performance
grid systems are expected to incur electricity bills that grow super-linearly
over time. In order to achieve cost effectiveness in these systems, it is
essential for the scheduling algorithms to exploit electricity price
variations, both in space and time, that are prevalent in the dynamic
electricity price markets. In this paper, we present a metascheduling algorithm
to optimize the placement of jobs in a compute grid which consumes electricity
from the day-ahead wholesale market. We formulate the scheduling problem as a
Minimum Cost Maximum Flow problem and leverage queue waiting time and
electricity price predictions to accurately estimate the cost of job execution
at a system. Using trace based simulation with real and synthetic workload
traces, and real electricity price data sets, we demonstrate our approach on
two currently operational grids, XSEDE and NorduGrid. Our experimental setup
collectively constitute more than 433K processors spread across 58 compute
systems in 17 geographically distributed locations. Experiments show that our
approach simultaneously optimizes the total electricity cost and the average
response time of the grid, without being unfair to users of the local batch
systems.Comment: Appears in IEEE Transactions on Parallel and Distributed System
Topology-aware GPU scheduling for learning workloads in cloud environments
Recent advances in hardware, such as systems with multiple GPUs and their availability in the cloud, are enabling deep learning in various domains including health care, autonomous vehicles, and Internet of Things. Multi-GPU systems exhibit complex connectivity among GPUs and between GPUs and CPUs. Workload schedulers must consider hardware topology and workload communication requirements in order to allocate CPU and GPU resources for optimal execution time and improved utilization in shared cloud environments.
This paper presents a new topology-aware workload placement strategy to schedule deep learning jobs on multi-GPU systems. The placement strategy is evaluated with a prototype on a Power8 machine with Tesla P100 cards, showing speedups of up to ≈1.30x compared to state-of-the-art strategies; the proposed algorithm achieves this result by allocating GPUs that satisfy workload requirements while preventing interference. Additionally, a large-scale simulation shows that the proposed strategy provides higher resource utilization and performance in cloud systems.This project is supported by the IBM/BSC Technology Center for Supercomputing
collaboration agreement. It has also received funding from the European Research Council (ERC) under the European Union’s Horizon
2020 research and innovation programme (grant agreement No 639595). It is
also partially supported by the Ministry of Economy of Spain under contract
TIN2015-65316-P and Generalitat de Catalunya under contract 2014SGR1051,
by the ICREA Academia program, and by the BSC-CNS Severo Ochoa program
(SEV-2015-0493). We thank our IBM Research colleagues Alaa Youssef
and Asser Tantawi for the valuable discussions. We also thank SC17 committee
member Blair Bethwaite of Monash University for his constructive feedback on the earlier drafts of this paper.Peer ReviewedPostprint (published version
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%
Adaptive space-time sharing with SCOJO.
Coscheduling is a technique used to improve the performance of parallel computer applications under time sharing, i.e., to provide better response times than standard time sharing or space sharing. Dynamic coscheduling and gang scheduling are two main forms of coscheduling. In SCOJO (Share-based Job Coscheduling), we have introduced our own original framework to employ loosely coordinated dynamic coscheduling and a dynamic directory service in support of scheduling cross-site jobs in grid scheduling. SCOJO guarantees effective CPU shares by taking coscheduling effects into consideration and supports both time and CPU share reservation for cross-site job. However, coscheduling leads to high memory pressure and still involves problems like fragmentation and context-switch overhead, especially when applying higher multiprogramming levels. As main part of this thesis, we employ gang scheduling as more directly suitable approach for combined space-time sharing and extend SCOJO for clusters to incorporate adaptive space sharing into gang scheduling. We focus on taking advantage of moldable and malleable characteristics of realistic job mixes to dynamically adapt to varying system workloads and flexibly reduce fragmentation. In addition, our adaptive scheduling approach applies standard job-scheduling techniques like a priority and aging system, backfilling or easy backfilling. We demonstrate by the results of a discrete-event simulation that this dynamic adaptive space-time sharing approach can deliver better response times and bounded relative response times even with a lower multiprogramming level than traditional gang scheduling.Dept. of Computer Science. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2004 .H825. Source: Masters Abstracts International, Volume: 43-01, page: 0237. Adviser: A. Sodan. Thesis (M.Sc.)--University of Windsor (Canada), 2004
Planificación consciente de la contención y gestión de recursos en arquitecturas multicore emergentes
Tesis inédita de la Universidad Complutense de Madrid, Facultad de Informática, Departamento de Arquitectura de Computadores y Automática, leÃda el 14-12-2021Chip multicore processors (CMPs) currently constitute the architecture of choice for mosto general-pùrpose computing systems, and they will likely continue to be dominant in the near future. Advances in technology have enabled to pack an increasing number of cores and bigger caches on the same chip. Nevertheless, contention on shared resources on CMPs -present since the advent of these architectures- still poses a big challenge. Cores in a CMP typically share a last-level cache (LLC) and other memory-related resources with the remaining cores, such as a DRAM controller and an interconnection network. This causes that co-running applications may intensively compete with each other for these shared resources, leading to substantial and uneven performance degradation...Los procesadores multinúcleo o CMPs (Chip Multicore Processors) son actualmente la arquitectura más usada por la mayorÃa de sistemas de computación de propósito
general, y muy probablemente se mantendrÃan en esa posición dominante en el futuro cercano. Los avances tecnológicos han permitido integrar progresivamente en el mismo chip más cores y aumentar los tamaños de los distintos niveles de
cache. No obstante, la contención de recursos compartidos en CMPs {presente desde la aparición de estas arquitecturas{ todavÃa representa un reto importante que afrontar. Los cores en un CMP comparten en la mayor parte de los diseños
una cache de último nivel o LLC (Last-Level Cache) y otros recursos, como el controlador de DRAM o una red de interconexión. La existencia de dichos recursos compartidos provoca en ocasiones que cuando se ejecutan dos o más aplicaciones simultáneamente en el sistema, se produzca una degradación sustancial y potencialmente desigual del rendimiento entre aplicaciones...Fac. de InformáticaTRUEunpu
Modeling and scheduling heterogeneous multi-core architectures
Om de prestatie van toekomstige processors en processorarchitecturen te evalueren wordt vaak gebruik gemaakt van een simulator die het gedrag en de prestatie van de processor modelleert. De prestatie bepalen van de uitvoering van een computerprogramma op een gegeven processorarchitectuur m.b.v. een simulator duurt echter vele grootteordes langer dan de werkelijke uitvoeringstijd. Dit beperkt in belangrijke mate de hoeveelheid experimenten die gedaan kunnen worden.
In dit doctoraatswerk werd het Multi-Program Performance Model (MPPM) ontwikkeld, een innovatief alternatief voor traditionele simulatie, dat het mogelijk maakt om tot 100.000x sneller een processorconfiguratie te evalueren. MPPM laat ons toe om nooit geziene exploraties te doen. Gebruik makend van dit raamwerk hebben we aangetoond dat de taakplanning cruciaal is om heterogene meerkernige processors optimaal te benutten.
Vervolgens werd een nieuwe manier voorgesteld om op een schaalbare manier de taakplanning uit te voeren, namelijk Performance Impact Estimation (PIE). Tijdens de uitvoering van een draad op een gegeven processorkern schatten we de prestatie op een ander type kern op basis van eenvoudig op te meten prestatiemetrieken. Zo beschikken we op elk moment over alle nodige informatie om een efficiënte taakplanning te doen. Dit laat ons bovendien toe te optimaliseren voor verschillende criteria zoals uitvoeringstijd, doorvoersnelheid of fairness
DESIGN AND EVALUATION OF RESOURCE ALLOCATION AND JOB SCHEDULING ALGORITHMS ON COMPUTATIONAL GRIDS
Grid, an infrastructure for resource sharing, currently has shown its importance in
many scientific applications requiring tremendously high computational power. Grid
computing enables sharing, selection and aggregation of resources for solving
complex and large-scale scientific problems. Grids computing, whose resources are
distributed, heterogeneous and dynamic in nature, introduces a number of fascinating
issues in resource management. Grid scheduling is the key issue in grid environment
in which its system must meet the functional requirements of heterogeneous domains,
which are sometimes conflicting in nature also, like user, application, and network.
Moreover, the system must satisfy non-functional requirements like reliability,
efficiency, performance, effective resource utilization, and scalability. Thus, overall
aim of this research is to introduce new grid scheduling algorithms for resource
allocation as well as for job scheduling for enabling a highly efficient and effective
utilization of the resources in executing various applications.
The four prime aspects of this work are: firstly, a model of the grid scheduling
problem for dynamic grid computing environment; secondly, development of a new
web based simulator (SyedWSim), enabling the grid users to conduct a statistical
analysis of grid workload traces and provides a realistic basis for experimentation in
resource allocation and job scheduling algorithms on a grid; thirdly, proposal of a new
grid resource allocation method of optimal computational cost using synthetic and
real workload traces with respect to other allocation methods; and finally, proposal of
some new job scheduling algorithms of optimal performance considering parameters
like waiting time, turnaround time, response time, bounded slowdown, completion
time and stretch time. The issue is not only to develop new algorithms, but also to
evaluate them on an experimental computational grid, using synthetic and real
workload traces, along with the other existing job scheduling algorithms.
Experimental evaluation confirmed that the proposed grid scheduling algorithms
possess a high degree of optimality in performance, efficiency and scalability
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