DOCSLIB.ORG

00 Multi-Threaded Servers: Design with Reusable Components, Performance Measurements and Analysis

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
00 Multi-Threaded Servers: Design with Reusable Components, Performance Measurements and Analysis 00 Multi-Threaded Servers: Design with reusable components, Performance Measurements and Analysis Gunidas Somadder B.E. A thesis submitted to the Faculty of Graduate Studies and Research in partial fMïlhent of the reqairements for the degree of Master of Engineering Ottawa-Carleton Institute for Electrical Engineering Faculty of Engineering Department of Systems and Cornputer Engineering Carleton University, Ottawa, Ontario, Canada February 12,1997 O 1997, Gurudas Somadder National Library Bibliothèque nationale of Canada du Canada Acquisitions and Acquisitions et Bbliographic Services services bibliographiques 395 WefIington Street 395, rue Wellington Ottawa ON KIA ON4 Ottawa ON KIA ON4 Canada Canada Ywr61B vmréffnnicd Our Isle Nom nirthence The author has granted a non- L'auteur a accordé une licence non exclusive licence allowing the exclusive permettant à la National Library of Canada to Bibliothèque nationale du Canada de reproduce, loan, distri'bute or seIl reproduire, prêter, distribuer ou copies of this thesis in microform, vendre des copies de cette thèse sous paper or electronic formats. la forme de microfiche/nlm, de reproduction sur papier ou sur format électronique. The author retains ownership of the L'auteur conserve la propriété du copyright in this thesis. Neither the droit d'auteur qui protège cette thèse. thesis nor substantid extracts fkom it Ni la thèse ni des extraits substantiels may be p~tedor othemise de celle-ci ne doivent être imprimés reproduced without the author's ou autrement reproduits sans son permission. autorisation. canada Abstract The first object of this research was to develop an efficient approach to build multi- threaded servers by using reusable components provided in the object-oriented fhmework Adaptive Communication Environment (ACE) descrii in [Sch94Aprl]. The thesis presents the pattern-based design, implementation and perfofmance measurements of different dtematives of multi-threaded servers for distributed applications. The multi- threaded approaches are compared based on their performance under different loads and system architectures, their execution overheads and cotz~umptionof shared system resources (such as memory and I/O ports). It is shom that for cenain system architectures, server multi-threading can improve the ovexall performance of the system by allowing for a more efficient use of the hardware resources. The impact of assigning priorities to the service requests (as opposed to the clients) and a rationale for establishg such priorities depending on the workload characteristics are also discussed. Another objective of the research was to fkd a way to exploit the design pattern used m object-oriented systems for pedormance analysis. Design pattems desmi recurriflg solutions to common problems fiom various application domains, and provide a more abstract view of the system behavior as they concentrate on the main interactions between the system components. It is shown that patterns can guide developers in choosing what to measure, in instrumenting the code for measurements and in interpreting the results. It is emphasized that an abstract behavioral model, such as the one provided by design patterns, is especially usenil in systems built with reusable components, both for understanding what the reused software does and its contriion to the overall performance. Acknowledgrnents 1 would like to express my deep gratitude to my supervisor, Dr. D. C. Petriu, for her vaiuable guidance, advice and encouragement throughout this research. 1 would aIso like to thank Dr. CM. Woodside and Dr. J. Rolia of the Real-Time and Distnbuted Systems (.R4DS) Group of the Department of Systems and Compter Engineering for their support and advice diiring the research. Many thanks to my colleagues, Istabrak, Fahim, Hesham, Marc, Alex, Cheryl and Leslie for their support, advice, help and encouragement during the course of this thesis. The f?nancial assistance of the Telecommunications Research Institute of Ontario (TRIO), through its opemting gant program, is gratefully acknowledged. Finally 1 would like to thank my parents, sisters and Iast but not the least, my brother-in- laws, for their invaluable support, patience, understanding and encouragement which made this thesis possible. Contents 1 Introduction 2. Threads and Threading Models Introduction .............................................................................................10 SoIaris 2.5 Multi-threading Architecture ................................................. 12 2.2.1 Processes and Threads ............................................................... 13 2.2.2 Solaris Multi-threaded Architecture ...........................O............. 14 Threading Models ............,,...........................œ...........œœœœ...œœ......o.œœœ.........1 7 Thread Priorities and Tbread-based Measmements ................................ 18 2.4.1 Thread Prionties ........................................................................ 18 2.4.2 ThTead-based Measurements ..................................................... 19 Benefits/Drawbacks of Thread-based Concurrent Rogramming ............ 20 2.5.1 Benefits of using Thread-based Concment Programming ....... 20 2.5-2 Drawbacks of using Thread-based Concurrent Programming ... 2 1 3 . The Adaptive Communication Environment 24 Introduction .......................................................................................... The ACE Tookit ................................................................................... 3.2.1 C* Wrappers ........................................................................ 3 .2.2 Class Categories and Frameworks ..................................O...... Design Patterns: Concept and Use .., ...... .. ......... .. 3.3. 1 The Reactor Pattern ................................................................ 3.3.2 The Acceptor Pattern .............................................................. 3.3.3 The Connector Pattern ............................................................ 3.3.4 The Active Object Pattern ...................................................... 4. Client/Server Design and Implementation 4.1 Introduction ........................................................................................... 4.2 Client,Server Architecture fiom an ACE Viewpoint ., ......................... 4.2.1 The Client ................................................................................ 4.2.2 The Server e............................................................................... 4.2.2.1 Single Threaded Server .. ..............................W......e. 4.2.2.2 The Thread-per-Reguest Server .............o......eO....... 4.2.2.3 The Thread-per-Client Server ................................ 4.2.2.4 Tbe Thread-Pool Server .................W.....................e. 4.3 System Architecture ....O. ...... .. .......~...mœ~.e.e.~œo~~.~...qo...m.~*..~~~.o.~o....~...~..... 4.3.1 Single-Threaded C/SArchitecture ..............................O............ 4.3.2 Thread-per-Request C/S Architecture .................... .................. 4.3.3 Thread-per-Client CIS Architecture ................. ........................ 4.3.4 Thread-Po01 C/S Architecture ................................................... 64 4.4 A Use Case Map Representation of the System Execution Cycle .........* 64 4.5 Systems with Layered Servers ... .....,...l...........w.......m.*m*....*..*............... 66 Experimental Setup and Measurements 68 Introduction ............................................................................................. 68 Experimental Setup .....,w..........,..oa........***.e*.*......*...*....*.......*...............69 5.2.1 Experiment ControUer and Data Logger ................. ..... ..*....*..... 70 5.2.2 DECALS Architecture .............................................*.................71 Measuement Results and Performance Analysis ...,........................ ... 72 Pattern-guided Mea~u~ementsand Analysis ... ....w..,.........m.œ..*....*...e**.... 79 5.4.1 Frequently executed patterns ..................... ............................... 80 5 -4-1 .1 Reactor Pattern ......*.......................*............*.*..........80 5.4.1.2 Active Object Pattern .........,......... .......................... 5.4.2 Detailed Measurement Results and Performance Anaiysis ....... Cornparison between the Thread-per-Client and the Thread-Pool Semer Models ........................................................................................ 6.3 Service Rior@ ............, ...,....*...............*...................................... 99 6.4 Experimental Setup ,........,...,....,*..........~.*................................... 1O0 6.5 Measuement Rdtsand Andysis for Service Priority ..........................* 101 vii 6.5.1 Measurement Red&for the Pure Server Arc.tecture ..................... 102 6.5.1.1 Effect of Changing Service Time Ratios ............O.....106 6-5-12 Impact of Changing the Number of Tbreads in the Thread-Pool ........................................................ 6.5.2 Measurement Results for the Layered Server Architecture ........ 109 6.6 Measurement Rdtsand Analysis for Class Priorify ............... .............. 1 12 7. Conchions 115 7.1 Summaxy ....................... ................. .......................... ........................... 115 7.2 FutureWork ....................... ........... ........................................................ 117 Appendix A Notations for Use Case Maps and UML 118 k 1 Use Case Map
Load more

Recommended publications
  • Leader/Followers
    Leader/Followers Douglas C. Schmidt, Carlos O’Ryan, Michael Kircher, Irfan Pyarali, and Frank Buschmann {schmidt, coryan}@uci.edu, {Michael.Kircher, Frank.Buschmann}@mchp.siemens.de, [email protected] University of California at Irvine, Siemens AG, and Washington University in Saint Louis The Leader/Followers architectural pattern provides an efficient concurrency model where multiple threads take turns sharing a set of event sources in order to detect, de- multiplex, dispatch, and process service requests that occur on these event sources. Example Consider the design of a multi-tier, high-volume, on-line transaction processing (OLTP) system. In this design, front-end communication servers route transaction requests from remote clients, such as travel agents, claims processing centers, or point-of-sales terminals, to back-end database servers that process the requests transactionally. After a transaction commits, the database server returns its results to the associated communication server, which then forwards the results back to the originating remote client. This multi-tier architecture is used to improve overall system throughput and reliability via load balancing and redundancy, respectively.It LAN WAN Front-End Back-End Clients Communication Servers Database Servers also relieves back-end servers from the burden of managing different communication protocols with clients. © Douglas C. Schmidt 1998 - 2000, all rights reserved, © Siemens AG 1998 - 2000, all rights reserved 19.06.2000 lf.doc 2 Front-end communication servers are actually ``hybrid'' client/server applications that perform two primary tasks: 1 They receive requests arriving simultaneously from hundreds or thousands of remote clients over wide area communication links, such as X.25 or TCP/IP.
    [Show full text]
  • A Survey of Architectural Styles.V4
    Survey of Architectural Styles Alexander Bird, Bianca Esguerra, Jack Li Liu, Vergil Marana, Jack Kha Nguyen, Neil Oluwagbeminiyi Okikiolu, Navid Pourmantaz Department of Software Engineering University of Calgary Calgary, Canada Abstract— In software engineering, an architectural style is a and implementation; the capabilities and experience of highest-level description of an accepted solution to a common developers; and the infrastructure and organizational software problem. This paper describes and compares a selection constraints [30]. These styles are not presented as out-of-the- of nine accepted architectural styles selected by the authors and box solutions, but rather a framework within which a specific applicable in various domains. Each pattern is presented in a software design may be made. If one were to say “that cannot general sense and with a domain example, and then evaluated in be called a layered architecture because the such and such a terms of benefits and drawbacks. Then, the styles are compared layer must communicate with an object other than the layer in a condensed table of advantages and disadvantages which is above and below it” then one would have missed the point of useful both as a summary of the architectural styles as well as a architectural styles and design patterns. They are not intended tool for selecting a style to apply to a particular project. The to be definitive and final, but rather suggestive and a starting paper is written to accomplish the following purposes: (1) to give readers a general sense of several architectural styles and when point, not to be used as a rule book but rather a source of and when not to apply them, (2) to facilitate software system inspiration.
    [Show full text]
  • The Need for Hardware/Software Codesign Patterns - a Toolbox for the New Digital Designer
    The need for Hardware/Software CoDesign Patterns - a toolbox for the new Digital Designer By Senior Consultant Carsten Siggaard, Danish Technological Institute May 30. 2008 Abstract Between hardware and software the level of abstraction has always differed a lot, this is not a surprise, hardware is an abstraction for software and the topics which is considered important by either a hardware developer or a software developer are quite different, making the communication between software and hardware developers (or even departments) difficult. In this report the software concept of design patterns is expanded into hardware, and the need for a new kind of design pattern, The Digital Design Pattern, is announced. Copyright © 2008 Danish Technological Institute Page 1 of 20 Contents Contents ............................................................................................................................................... 2 Background .......................................................................................................................................... 4 What is a design pattern ....................................................................................................................... 4 Three Disciplines when using Design Patterns ................................................................................ 5 Pattern Hatching ........................................................................................................................... 6 Pattern Mining.............................................................................................................................
    [Show full text]
  • Active Object
    Active Object an Object Behavioral Pattern for Concurrent Programming R. Greg Lavender Douglas C. Schmidt [email protected] [email protected] ISODE Consortium Inc. Department of Computer Science Austin, TX Washington University, St. Louis An earlier version of this paper appeared in a chapter in the book ªPattern Languages of Program Design 2º ISBN 0-201-89527-7, edited by John Vlissides, Jim Coplien, and Norm Kerth published by Addison-Wesley, 1996. : Output : Input Handler Handler : Routing Table : Message Abstract Queue This paper describes the Active Object pattern, which decou- 3: enqueue(msg) ples method execution from method invocation in order to : Output 2: find_route(msg) simplify synchronized access to a shared resource by meth- Handler ods invoked in different threads of control. The Active Object : Message : Input pattern allows one or more independent threads of execution Queue Handler 1: recv(msg) to interleave their access to data modeled as a single ob- ject. A broad class of producer/consumer and reader/writer OUTGOING OUTGOING MESSAGES GATEWAY problems are well-suited to this model of concurrency. This MESSAGES pattern is commonly used in distributed systems requiring INCOMING INCOMING multi-threaded servers. In addition,client applications (such MESSAGES MESSAGES as windowing systems and network browsers), are increas- DST DST ingly employing active objects to simplify concurrent, asyn- SRC SRC chronous network operations. 1 Intent Figure 1: Connection-Oriented Gateway The Active Object pattern decouples method execution from method invocation in order to simplify synchronized access to a shared resource by methods invoked in different threads [2]. Sources and destinationscommunicate with the Gateway of control.
    [Show full text]
  • Performance Analysis of the Reactor Pattern in Network Services
    Performance Analysis of the Reactor Pattern in Network Services Swapna Gokhale1, Aniruddha Gokhale2, Jeff Gray3, Paul Vandal1, Upsorn Praphamontripong1 1University of Connecticut 2Vanderbilt University Dept. of Computer Science Dept. of Electrical Engineering and Engineering and Computer Science Storrs, CT 06269 USA Nashville, TN 37235 USA [email protected] [email protected] 3University of Alabama at Birmingham Dept of Computer and Information Science Birmingham, AL USA [email protected] Abstract 1. Introduction Service oriented computing (SoC), which is made feasi- ble by middleware-based distributed systems, is an emerg- ing technology to provide the next-generation services to meet societal needs ranging from basic necessities, such as The growing reliance on services provided by software education, energy, communications and healthcare to emer- applications places a high premium on the reliable and ef- gency and disaster management. For SOC to be successful ficient operation of these applications. A number of these in meeting the demands of society, assurance on the perfor- applications follow the event-driven software architecture mance of these services is necessary. Since these services style since this style fosters evolvability by separating event are primarily built using communication middleware, the handling from event demultiplexing and dispatching func- problem reduces to the issue of performance assurance of tionality. The event demultiplexing capability, which ap- the middleware platforms. pears repeatedly across a class of event-driven applica- Middleware typically comprises a number of building tions, can be codified into a reusable pattern, such as the blocks, which are essentially patterns-based reusable soft- Reactor pattern. In order to enable performance analysis of ware frameworks.
    [Show full text]
  • The Design and Use of the ACE Reactor an Object-Oriented Framework for Event Demultiplexing
    The Design and Use of the ACE Reactor An Object-Oriented Framework for Event Demultiplexing Douglas C. Schmidt and Irfan Pyarali g fschmidt,irfan @cs.wustl.edu Department of Computer Science Washington University, St. Louis 631301 1 Introduction create concrete event handlers by inheriting from the ACE Event Handler base class. This class specifies vir- This article describes the design and implementation of the tual methods that handle various types of events, such as Reactor pattern [1] contained in the ACE framework [2]. The I/O events, timer events, signals, and synchronization events. Reactor pattern handles service requests that are delivered Applications that use the Reactor framework create concrete concurrently to an application by one or more clients. Each event handlers and register them with the ACE Reactor. service of the application is implemented by a separate event Figure 1 shows the key components in the ACE Reactor. handler that contains one or more methods responsible for This figure depicts concrete event handlers that implement processing service-specific requests. In the implementation of the Reactor pattern described in this paper, event handler dispatching is performed REGISTERED 2: accept() by an ACE Reactor.TheACE Reactor combines OBJECTS 5: recv(request) 3: make_handler() the demultiplexing of input and output (I/O) events with 6: process(request) other types of events, such as timers and signals. At Logging Logging Logging Logging Handler Acceptor LEVEL thecoreoftheACE Reactor implementation is a syn- LEVEL Handler Handler chronous event demultiplexer, such as select [3] or APPLICATION APPLICATION Event Event WaitForMultipleObjects [4]. When the demulti- Event Event Handler Handler Handler plexer indicates the occurrence of designated events, the Handler ACE Reactor automatically dispatches the method(s) of 4: handle_input() 1: handle_input() pre-registered event handlers, which perform application- specified services in response to the events.
    [Show full text]
  • Principles of Software Design Concurrency and Parallelism
    Concurrency and Parallelism Principles of Software Design Concurrency and Parallelism Robert Luko´ka [email protected] www.dcs.fmph.uniba.sk/~lukotka M-255 Robert Luko´ka Concurrency and Parallelism Concurrency and Parallelism Concurrency and Parallelism Concurrency - is the ability of dierent parts or units of a program, algorithm, or problem to be executed out-of-order or in partial order, without aecting the nal outcome. Parallelism - calculations or the execution of processes are carried out simultaneously. Concurrency allows for parallel execution. Robert Luko´ka Concurrency and Parallelism Concurrency and Parallelism Concurrency and Parallelism Concurrency is useful even without parallel computing (it makes sense to use more threads even if we have only one processor): Ecient allocation of resources - while a thread waits for something, another thread may be executed. You do not need threads to get concurrent behavior, see e.g. select system call. You do not know the order on which your code is executed. But it should not matter. Robert Luko´ka Concurrency and Parallelism Concurrency and Parallelism What could possibly go wrong? int etx_rcvd = FALSE; void WaitForInterrupt() { etx_rcvd = FALSE; while (!ext_rcvd) { counter++; } } Robert Luko´ka Concurrency and Parallelism Concurrency and Parallelism What could possibly go wrong? Compiler does obvious optimization. int etx_rcvd = FALSE; void WaitForInterrupt() { while (1) { counter++; } } Robert Luko´ka Concurrency and Parallelism Concurrency and Parallelism Race conditions OK, that was a bit silly, this is a more standard examples (Python, C++): //Example 1 if x == 5: x = x * 2 //Example2 x = x + 1 //Example3 x += 1 //Example4 (C++) x++; Robert Luko´ka Concurrency and Parallelism Concurrency and Parallelism Race conditions Each of the examples can lead to surprising behavior provided that another process can modify x concurrently.
    [Show full text]
  • Stage Scheduling for CPU-Intensive Servers
    UCAM-CL-TR-781 Technical Report ISSN 1476-2986 Number 781 Computer Laboratory Stage scheduling for CPU-intensive servers Minor E. Gordon June 2010 15 JJ Thomson Avenue Cambridge CB3 0FD United Kingdom phone +44 1223 763500 http://www.cl.cam.ac.uk/ c 2010 Minor E. Gordon This technical report is based on a dissertation submitted December 2009 by the author for the degree of Doctor of Philosophy to the University of Cambridge, Jesus College. Technical reports published by the University of Cambridge Computer Laboratory are freely available via the Internet: http://www.cl.cam.ac.uk/techreports/ ISSN 1476-2986 Stage scheduling for CPU-intensive servers Minor E. Gordon Summary The increasing prevalence of multicore, multiprocessor commodity hardware calls for server software architectures that are cycle-efficient on individual cores and can maximize concurrency across an entire machine. In order to achieve both ends this dissertation ad- vocates stage architectures that put software concurrency foremost and aggressive CPU scheduling that exploits the common structure and runtime behavior of CPU-intensive servers. For these servers user-level scheduling policies that multiplex one kernel thread per physical core can outperform those that utilize pools of worker threads per stage on CPU-intensive workloads. Boosting the hardware efficiency of servers in userspace means a single machine can handle more users without tuning, operating system modifications, or better hardware. Contents 1 Introduction 9 1.1 Servers . 9 1.2 Stages . 10 1.3 An image processing server . 10 1.4 Optimizing CPU scheduling for throughput . 11 1.5 Outline . 13 1.5.1 Results .
    [Show full text]
  • Reactive Programming
    Reactive programming Lessons learned Tomasz Nurkiewicz You must be this tall to practice reactive programming [...] a very particular set of skills, skills [...] acquired over a very long career. Skills that make me a nightmare for people like you Liam Neeson on reactive programming Who am I? I built complex reactive systems * not really proud about the “complex” part 1000+ Akka cluster nodes Tens of thousands of RPS on a single node Beat C10k problem ...and C100k I wrote a book with the word “reactive” in the title May you live in interesting times Chinese curse May you support interesting codebase me 1. Fetch user by name from a web service 2. If not yet in database, store it 3. Load shopping cart for user 4. Count total price of items 5. Make single payment 6. Send e-mail for each individual item, together with payment ID User user = ws.findUserByName(name); if (!db.contains(user.getSsn())) { db.save(user); } List<Item> cart = loadCart(user); double total = cart.stream() .mapToDouble(Item::getPrice) .sum(); UUID id = pay(total); cart.forEach(item -> sendEmail(item, id)); User user = ws.findUserByName(name) Mono<User> user = ws.findUserByName(name) boolean contains = db.contains(user.getSsn()) Mono<Boolean> contains = db.contains(user.getSsn()) if (!db.contains(user.getSsn())) { db.save(user); } user -> db .contains(user.getSsn()) //Mono<Bool>, true/false .filter(contains -> contains) //Mono<Bool>, true/empty .switchIfEmpty(db.save(user)) //if empty, //replace with db.save() User user = ws.findUserByName(name); if (!db.contains(user.getSsn())) { db.save(user); } List<Item> cart = loadCart(user); double total = cart.stream() .mapToDouble(Item::getPrice) .sum(); UUID id = pay(total); cart.forEach(item -> sendEmail(item, id)); Now, take a deep breath..
    [Show full text]
  • Conceptual Architecture Patterns
    HASSO - PLATTNER - INSTITUT für Softwaresystemtechnik an der Universität Potsdam Conceptual Architecture Patterns Technische Berichte des Hasso-Plattner-Instituts für Softwaresystemtechnik an der Universität Potsdam Technische Berichte des Hasso-Plattner-Instituts für Softwaresystemtechnik an der Universität Potsdam 2 Conceptual Architecture Patterns: FMC-based Representations Bernhard Gröne and Frank Keller (eds.) April 2004 Bibliografische Information Der Deutschen Bibliothek Die Deutsche Bibliothek verzeichnet diese Publikation in der Deutschen Nationalbibliografie; detaillierte bibliografische Daten sind im Internet über http://dnb.ddb.de abrufbar. Die Reihe Technische Berichte des Hasso-Plattner-Instituts für Softwaresystemtechnik an der Universität Potsdam erscheint aperiodisch. Herausgeber: Professoren des Hasso-Plattner-Instituts für Softwaresystemtechnik an der Universität Potsdam Redaktion Bernhard Gröne und Frank Keller EMail {bernhard.groene, frank.keller}@hpi.uni-potsdam.de Vertrieb: Universitätsverlag Potsdam Postfach 60 15 53 14415 Potsdam Fon +49 (0) 331 977 4517 Fax +49 (0) 331 977 4625 e-mail: [email protected] http://info.ub.uni-potsdam.de/verlag.htm Druck allprintmedia gmbH Blomberger Weg 6a 13437 Berlin email: [email protected] © Hasso-Plattner-Institut für Softwaresystemtechnik an der Universität Potsdam, 2004 Dieses Manuskript ist urheberrechtlich geschützt. Es darf ohne vorherige Genehmigung der Herausgeber nicht vervielfältigt werden. Heft 2 (2004) ISBN 3-935024-98-3 ISSN 1613-5652 Conceptual Architecture Patterns: FMC–based Representations Bernhard Gröne and Frank Keller (editors) Research assistants of the chair “Modeling of Software–intensive Systems” Hasso–Plattner–Institute for Software Systems Engineering P.O. Box 900460, 14440 Potsdam, Germany E-mail: {bernhard.groene, frank.keller}@hpi.uni-potsdam.de Abstract This document presents the results of the seminar “Conceptual Architecture Patterns” of the winter term 2002 in the Hasso–Plattner–Institute.
    [Show full text]
  • Leader/Followers a Design Pattern for Efficient Multi-Threaded I/O
    Leader/Followers A Design Pattern for Efficient Multi-threaded I/O Demultiplexing and Dispatching Douglas C. Schmidt and Carlos O’Ryan g fschmidt,coryan @uci.edu Electrical and Computer Engineering Dept. University of California, Irvine, CA 92697, USA Michael Kircher Irfan Pyarali [email protected] [email protected] Siemens Corporate Technology Department of Computer Science, Washington University Munich, Germany St. Louis, MO 63130, USA 1 Intent The front-end communication servers are actually “hybrid” client/server applications that perform two primary tasks. The Leader/Followers design pattern provides a concurrency First, they receive requests arriving simultaneously from hun- model where multiple threads can efficiently demultiplex dreds or thousands of remote clients over wide area commu- events and dispatch event handlers that process I/O handles nication links, such as X.25 or the TCP/IP. Second, they vali- shared by the threads. date the remote client requests and forward valid requests over TCP/IP connections to back-end database servers. In contrast, the back-end database servers are “pure” servers that perform 2 Example the designated transactions. After a transaction commits, the database server returns its results to the associated commu- Consider the design of a multi-tier, high-volume, on-line trans- nication server, which then forwards the results back to the action processing (OLTP) system shown in the following fig- originating remote client. ure. In this design, front-end communication servers route FRONT--END BACK--END The servers in this OLTP system spend most of their time COMM.. SERVERS DATABASE SERVERS processing various types of I/O operations in response to re- quests.
    [Show full text]
  • Splay: a Toolkit for the Design and Evaluation of Large Scale Distributed Systems
    UNIVERSITÉ DE NEUCHÂTEL Splay: A toolkit for the design and evaluation of Large Scale Distributed Systems Thèse présentée le 27 juin 2014 à la Faculté des Sciences de l’Université de Neuchâtel pour l’obtention du grade de docteur ès sciences par Lorenzo Leonini acceptée sur proposition du jury: Prof. Pascal Felber Université de Neuchâtel directeur de thèse Prof. Peter Kropf Université de Neuchâtel rapporteur Dr Etienne Rivière Université de Neuchâtel rapporteur Prof. Vivien Quéma INP, Grenoble rapporteur Prof. Spyros Voulgaris VU University, Amsterdam rapporteur Faculté des sciences Secrétariat-décanat de Faculté Rue Emile-Argand 11 2000 Neuchâtel - Suisse Tél: + 41 (0)32 718 2100 E-mail: [email protected] IMPRIMATUR POUR THESE DE DOCTORAT La Faculté des sciences de l'Université de Neuchâtel autorise l'impression de la présente thèse soutenue par Monsieur Lorenzo LEONINI Titre: “Splay: A toolkit for the design and evaluation of Large Scale Distributed Systems” sur le rapport des membres du jury composé comme suit: • Prof. Pascal Felber, Université de Neuchâtel, directeur de thèse • Prof. Peter Kropf, Université de Neuchâtel • Dr Etienne Rivière, Université de Neuchâtel • Prof. Vivien Quéma, INP, Grenoble, France • Prof. Spyros Voulgaris, VU University, Amsterdam, Pays-Bas Neuchâtel, le 30 avril 2014 Le Doyen, Prof. P. Kropf Imprimatur pour thèse de doctorat www.unine.ch/sciences To my family. Acknowledgements First, I would like to thank my adviser, Prof. Pascal Felber, for all his guiding, advice, understanding and for our many shared sporting activities during my PhD studies. I would also like to thank Dr. Etienne Rivière for our collaboration and all the nice moments spent together.
    [Show full text]