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88
Coordinated Allocation and Scheduling of Multiple Resources in Real-time Operating Systems
"... Distributed real-time embedded (DRE) systems are key components of critical infrastructure including surveillance, target tracking, electric grid management, traffic control, avionics, and communications systems. They require (1) the coordinated management of multiple resources, such as the CPU, net ..."
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Distributed real-time embedded (DRE) systems are key components of critical infrastructure including surveillance, target tracking, electric grid management, traffic control, avionics, and communications systems. They require (1) the coordinated management of multiple resources, such as the CPU, network, and disk, (2) end-to-end (E2E) real-time guarantees across the use of multiple resources, and (3) feedback control across multiple resources. None of these properties is supported as a first-class feature within the state-of-theart real-time operating systems, but are left out as an inconvenient detail to be managed by DRE application programmers. In this paper, we shed light on this fundamental problem and make the case for greater research into the development of theory and a runtime systems for coordinated allocation and scheduling of multiple resources in real-time operating systems. We also present the outlines of our proposed solution approach, called the Multiple Resource Allocation and Scheduling (MURALS) framework, that aims to bridge this gap between the need for E2E timing requirements and the techniques to coordinate the use of multiple resources. 1.
Maintaining flow isolation in work-conserving flow aggregation
- in Proc. IEEE GLOBECOM Conference
, 2005
"... Abstract — In order to improve the scalability of scheduling protocols with bounded end-to-end delay, much effort has focused on reducing the amount of per-flow state at routers. One technique to reduce this state is flow aggregation, in which multiple individual flows are aggregated into a single a ..."
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Abstract — In order to improve the scalability of scheduling protocols with bounded end-to-end delay, much effort has focused on reducing the amount of per-flow state at routers. One technique to reduce this state is flow aggregation, in which multiple individual flows are aggregated into a single aggregate flow. In addition to reducing per-flow state, flow aggregation has the advantage of a per-hop delay that is inversely proportional to the rate of the aggregate flow, while in the case of no aggregation, the per-hop delay is inversely proportional to the (smaller) rate of the individual flow. Flow aggregation in general is non-work-conserving. Recently, a work-conserving flow aggregation technique has been proposed. However, it has the disadvantage that the end-to-end delay of an individual flow is related to the burstiness of other flows sharing its aggregate flow. Here, we show how work-conserving flow aggregation may be performed without this drawback, that is, the end-to-end delay of an individual flow is independent of the burstiness of other flows. I.
Robustness Study of MBAC Algorithms
- In ISCC
, 2008
"... Abstract — Measurement based admission control (MBAC) has long been recognized as an important method for providing stochastic service guarantees. The main work in the literature has mostly been on finding optimal MBAC algorithms that maximize network utilization. On the other hand, a critical issue ..."
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Abstract — Measurement based admission control (MBAC) has long been recognized as an important method for providing stochastic service guarantees. The main work in the literature has mostly been on finding optimal MBAC algorithms that maximize network utilization. On the other hand, a critical issue for MBAC, which is the robustness of an MBAC algorithm in meeting the required quality of service (QoS) under changing traffic conditions, has long been overlooked and few results are available. In this paper, we investigate the robustness of MBAC in meeting the QoS target. Specifically we evaluate three representative MBAC algorithms and show their weaknesses and strengths through comparisons with an ideal admission controller. I.
Measurement-Based Admission Control for Bufferless Multiplexers
, 2001
"... In this paper we study measurement--based admission control for bufferless multiplexing, which is very attractive for real--time traffic. We first discuss a novel Large Deviations (LD) approach to measurement--based admission control. We then provide an extensive review of the existing literature ..."
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In this paper we study measurement--based admission control for bufferless multiplexing, which is very attractive for real--time traffic. We first discuss a novel Large Deviations (LD) approach to measurement--based admission control. We then provide an extensive review of the existing literature on measurement--based admission control.
Statistical admission control using delay distribution measurements
- ACM Trans. on Multimedia Computing, Commn, and Apps
, 2006
"... Growth of performance sensitive applications, such as voice and multimedia, has led to widespread adoption of resource virtualization by a variety of service providers (xSPs). For instance, Internet Service Providers (ISPs) increasingly differentiate their offerings by means of customized services, ..."
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Growth of performance sensitive applications, such as voice and multimedia, has led to widespread adoption of resource virtualization by a variety of service providers (xSPs). For instance, Internet Service Providers (ISPs) increasingly differentiate their offerings by means of customized services, such as virtual private networks (VPN) with Quality of Service (QoS) guarantees or QVPNs. Similarly Storage Service Providers (SSPs) use storage area networks (SAN)/network attached storage (NAS) technology to provision virtual disks with QoS guarantees or QVDs. The key challenge faced by these xSPs is to maximize the number of virtual resource units they can support by exploiting the statistical multiplexing nature of the customers ’ input request load. While a number of measurement-based admission control algorithms utilize statistical multiplexing along the bandwidth dimension, they do not satisfactorily exploit statistical multiplexing along the delay dimension to guarantee distinct per-virtualunit delay bounds. This article presents Delay Distribution Measurement (DDM) based admission control algorithm, the first measurement-based approach that effectively exploits statistical multiplexing along the delay dimension. In other words, DDM exploits the well-known fact that the actual delay experienced by most service requests (packets or disk I/O requests) for a virtual unit is usually far smaller than its worst-case delay bound requirement because multiple virtual units rarely send request bursts at the same time. Additionally, DDM supports virtual units with distinct probabilistic delay guarantees—virtual units that can tolerate more delay violations can reserve fewer resources than those that tolerate less, even though they require the same delay bound. Comprehensive trace-driven performance evaluation of QVPNs (using Voice over IP traces) and QVDs (using video
Adaptive Scheduling using Online Measurements for Efficient Delivery of Quality of Service
, 2004
"... DMS-0112069. Any opinions, findings, and conclusions or recommendations expressed in this material are ..."
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DMS-0112069. Any opinions, findings, and conclusions or recommendations expressed in this material are
KBAC: Knowledge-Based Admission Control
"... Abstract—Many methods have been proposed in the literature to perform admission control in order to provide a sufficient level of Quality of Service (QoS) to accepted flows. In this paper, we introduce a novel data-driven method based on a timevarying model that we refer to as Knowledge-Based Admiss ..."
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Abstract—Many methods have been proposed in the literature to perform admission control in order to provide a sufficient level of Quality of Service (QoS) to accepted flows. In this paper, we introduce a novel data-driven method based on a timevarying model that we refer to as Knowledge-Based Admission Control solution (KBAC). Our KBAC solution consists of three main stages: (i) collect measurements on the on-going traffic over the communication link; (ii) maintain an up-to-date broad view of the link behavior, and feed it to a Knowledge Plane; (iii) model the observed link behavior by a mono-server queue whose parameters are set automatically and which predicts the expected QoS if a flow requesting admission were to be accepted. Our KBAC solution provides a probabilistic guarantee whose admission threshold is either expressed, as a bounded delay or as a bounded loss rate. We run extensive simulations to assess the behavior of our KBAC solution in the case of a delay threshold. The results show that our KBAC solution leads to a good trade-off between flow performance and resource utilization. This ability stems from the quick and automatic adjustment of its admission policy according to the actual variations on the traffic conditions. I.
DDM: Statistical Admission Control Using Delay Distribution Measurement
- IN PROCEEDINGS OF THE 2004 ACM INTERNATIONAL CONFERENCE ON MULTIMEDIA
, 2004
"... Measurement-based admission control algorithms exploit the statistical multiplexing nature of input traffic to admit more flows into a system than is possible when assuming that each admitted flow is fully loaded. However, most previous measurement-based admission control algorithms did not have a s ..."
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Measurement-based admission control algorithms exploit the statistical multiplexing nature of input traffic to admit more flows into a system than is possible when assuming that each admitted flow is fully loaded. However, most previous measurement-based admission control algorithms did not have a satisfactory solution to the problem of guaranteeing distinct per-flow delay bounds while exploiting statistical multiplexing. This paper presents a novel technique, called Delay Distribution Measurement (DDM) based admission control algorithm, which effectively exploits statistical multiplexing by dynamically measuring the distribution of the ratios between actual packet delay and worst-case delay bound. With this delay ratio distribution, DDM is able to gauge the actual load of a system, estimate the actual resource requirement of new flows with distinct delay bound requirements, and eventually determine whether to admit them. The DDM algorithm develops a novel quantitative framework to exploit the well known fact that the actual delay experienced by most packets of a real-time flow is usually far smaller than its worst-case delay bound requirement. This framework also provides the additional flexibility to support flows with probabilistic delay bound requirements, i.e., flows for which a certain percentage of delay bound violations is tolerable. Flows that can tolerate more delay bound violations can reserve less resource than those that tolerate less, even though they have the same delay bound requirement. A comprehensive simulation study using Voice over IP traces shows that, when compared to deterministic admission control algorithms, the DDM algorithm can potentially increase the number of admitted flows (and link utilization) by up to a factor of 3.0 when the delay vio...
Profit-Oriented Resource Allocation Using Online Scheduling in Flexible Heterogeneous Networks. accepted by Telecommunication Systems
, 2005
"... flexible heterogeneous networks ∗∗ ..."
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