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SEDA: An Architecture for Well-Conditioned, Scalable Internet Services
, 2001
"... We propose a new design for highly concurrent Internet services, whichwe call the staged event-driven architecture (SEDA). SEDA is intended ..."
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Cited by 522 (10 self)
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We propose a new design for highly concurrent Internet services, whichwe call the staged event-driven architecture (SEDA). SEDA is intended
Analysis of multi-server systems via dimensionality reduction of Markov chains
- School of Computer Science, Carnegie Mellon University
, 2005
"... The performance analysis of multiserver systems is notoriously hard, especially when the system involves resource sharing or prioritization. We provide two new analytical tools for the performance analysis of multiserver systems: moment matching algorithms and dimensionality reduction of Markov chai ..."
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Cited by 22 (4 self)
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The performance analysis of multiserver systems is notoriously hard, especially when the system involves resource sharing or prioritization. We provide two new analytical tools for the performance analysis of multiserver systems: moment matching algorithms and dimensionality reduction of Markov chains (DR). Moment matching algorithms allow us to approximate a general distribution with a phase type (PH) distribution. Our moment matching algorithms improve upon existing ones with respect to the computational efficiency (we provide closed form solutions) as well as the quality and generality of the solution (the first three moments of almost any nonnegative distribution are matched). Approximating job size and interarrival time distributions by PH distributions enables modeling a multiserver system by a Markov chain, so that the performance of the system is given by analyzing the Markov chain. However, when the multiserver system involves resource sharing or prioritization, the Markov chain often has a multidimensionally infinite state space, which makes the analysis computationally hard. DR allows us to closely approximate a multidimensionally infinite Markov chain with a Markov
An Architecture for Highly Concurrent, Well-Conditioned Internet Services
, 2002
"... This dissertation presents an architecture for handling the massive concurrency and load conditioning demands of busy Internet services. Our thesis is that existing programming models and operating system structures do not adequately meet the needs of complex, dynamic Internet servers, which must ..."
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Cited by 19 (1 self)
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This dissertation presents an architecture for handling the massive concurrency and load conditioning demands of busy Internet services. Our thesis is that existing programming models and operating system structures do not adequately meet the needs of complex, dynamic Internet servers, which must support extreme concurrency (on the order of tens of thousands of client connections) and experience load spikes that are orders of magnitude greater than the average. We propose a new software framework, called the staged event-driven architecture (or SEDA), in which applications are constructed as a network of event-driven stages connected with explicit queues. In this model, each stage embodies a robust, reusable software component that performs a subset of request processing. By performing admission control on each event queue, the service can be well-conditioned to load, preventing resources from being overcommitted when demand exceeds service capacity. SEDA employs dynamic control to tune runtime parameters (such as the scheduling parameters of each stage) automatically, as well as to manage load, for example, by performing adaptive load shedding. In this
accept()able strategies for improving web server performance
- IN PROC. 2004 USENIX ANNUAL TECH. CONFERENCE
, 2004
"... This paper evaluates techniques for improving the performance of three architecturally different web servers. We study strategies for effectively accepting incoming connections under conditions of high load. Our experimental evaluation shows that the method used to accept new connection requests can ..."
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Cited by 16 (4 self)
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This paper evaluates techniques for improving the performance of three architecturally different web servers. We study strategies for effectively accepting incoming connections under conditions of high load. Our experimental evaluation shows that the method used to accept new connection requests can significantly impact server performance. By modifying each server’s accept strategy, we improve the performance of the kernel-mode TUX server, the multithreaded Knot server and the event-driven ¡ server. Under two different workloads, we improve the throughput of these servers by as much as 19 % – 36 % for TUX, 0% – 32 % for Knot, and 39 % – 71 % for the ¡ server. Interestingly, the performance improvements realized by the usermode ¡ server allow it to obtain performance that rivals an unmodified TUX server.
Self-Adapting Concurrency: The DMonA Architecture
, 2002
"... A major problem in todays Internet servers is that they suffer from extreme peak loads. Traditional (operating) systems are designed to perform extremely well under heavy load conditions. However, it is not feasible to over-provision resources only to support peak loads. A key factor to deal with su ..."
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Cited by 13 (9 self)
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A major problem in todays Internet servers is that they suffer from extreme peak loads. Traditional (operating) systems are designed to perform extremely well under heavy load conditions. However, it is not feasible to over-provision resources only to support peak loads. A key factor to deal with such peak loads is internal concurrency control. We have developed a component based architecture (DMonA), which allows to adapt internal concurrency according to measured throughput. Performance tests show that DMonA outperforms traditional approaches, while it is still very manageable thanks to the underlying DiPS component architecture.
Exploring the Performance of Select-Based Internet Servers
, 2001
"... this paper is largely motivated by this recent work by Chandra and Mosberger [6]. We believe that their work demonstrates that even simple server designs exhibit a wide range of variation in performance that is not well understood. In this paper we attempt to characterize the behaviour of some of th ..."
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Cited by 11 (5 self)
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this paper is largely motivated by this recent work by Chandra and Mosberger [6]. We believe that their work demonstrates that even simple server designs exhibit a wide range of variation in performance that is not well understood. In this paper we attempt to characterize the behaviour of some of these design options and use these results to gain insight into some of the issues affecting server designs in general
The Staged Event-Driven Architecture for Highly-Concurrent Server Applications
, 2000
"... We propose a new design for highly-concurrent server applications such as Internet services. This design, the staged event-driven architecture (SEDA), is intended to support massive concurrency demands for a wide range of applications. In SEDA, applications are constructed as a set of event-driven s ..."
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Cited by 9 (1 self)
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We propose a new design for highly-concurrent server applications such as Internet services. This design, the staged event-driven architecture (SEDA), is intended to support massive concurrency demands for a wide range of applications. In SEDA, applications are constructed as a set of event-driven stages separated by queues. This design allows services to be well-conditioned to load, preventing resources from being overcommitted when demand exceeds service capacity. Decomposing services into a set of stages enables modularity and code reuse, as well as the development of debugging tools for complex event-driven applications. We present the SEDA design, as well as Sandstorm, an Internet services platform based on this architecture. We evaluate the use of Sandstorm through two applications: A simple HTTP server benchmark and a packet router for the Gnutella peer-to-peer file sharing network. 1 Introduction The Internet presents a systems problem of unprecedented scale: that of supporti...
Service Differentiation in Web Caching and Content Distribution
"... Service differentiation in web caching and content distribution will result in significant technical and economic efficiency gains, to the benefit of both content publishers and service providers. Through preferential storage allocation and coordinated transitioning of objects across priority queues ..."
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Cited by 4 (1 self)
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Service differentiation in web caching and content distribution will result in significant technical and economic efficiency gains, to the benefit of both content publishers and service providers. Through preferential storage allocation and coordinated transitioning of objects across priority queues, we demonstrate a QoS caching scheme that achieves quantifiable service differentiation with Httle efficiency overhead. We develop and empirically validate a model to quantify, predict, and compare the performance of traditional and servicedifferentiated caching schemes.
TCP connection management mechanisms for improving internet server performance
, 2005
"... Abstract — This paper investigates TCP connection management mechanisms in order to understand the behaviour and improve the performance of Internet servers during overload conditions such as flash crowds. We study several alternatives for implementing TCP connection establishment, reviewing approac ..."
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Cited by 3 (0 self)
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Abstract — This paper investigates TCP connection management mechanisms in order to understand the behaviour and improve the performance of Internet servers during overload conditions such as flash crowds. We study several alternatives for implementing TCP connection establishment, reviewing approaches taken by existing TCP stacks as well as proposing new mechanisms to improve server throughput and reduce client response times under overload. We implement some of these mechanisms in Linux and evaluate their performance. Our evaluation demonstrates that connection establishment mechanisms that eliminate the TCP-level retransmission of connection attempts by clients can increase server throughput by up to 40 % and reduce client response times by two orders of magnitude. Additionally we evaluate the cost of supporting half-closed connections at the server and assess the impact of an abortive release of connections by clients on the throughput of an overloaded server. We observe that mechanisms that do not support half-closed connections additionally improve server throughput by more than 15%. I.
SOFTScale: Stealing Opportunistically For Transient Scaling Anshul Gandhi ∗
, 2012
"... those of the author and should not be interpreted as representing the official policies, either expressed or implied, of Dynamic capacity provisioning is a well studied approach to handling gradual changes in data center load. However, abrupt spikes in load are still problematic in that the work in ..."
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Cited by 2 (1 self)
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those of the author and should not be interpreted as representing the official policies, either expressed or implied, of Dynamic capacity provisioning is a well studied approach to handling gradual changes in data center load. However, abrupt spikes in load are still problematic in that the work in the system rises very quickly during the setup time needed to turn on additional capacity. Performance can be severely affected even if it takes only 5 seconds to bring additional capacity online. In this paper, we propose SOFTScale, an approach to handling load spikes in multi-tier data centers without having to over-provision resources. SOFTScale works by opportunistically stealing resources from other tiers to alleviate the bottleneck tier, even when the tiers are carefully provisioned at capacity. SOFTScale is especially useful during the transient overload periods when additional capacity is being brought online. Via implementation on a 28-server multi-tier testbed, we investigate a range of possible load spikes, including an artificial doubling or tripling of load, as well as large spikes in real traces. We find that SOFTScale can meet our stringent 95th percentile response time Service Level Agreement goal of 500ms without using any additional resources even under some extreme load spikes that would
