pr\u00e9sentent<\/p>\n\n\n\n
Autoris\u00e9 \u00e0 pr\u00e9senter ses travaux en vue de l\u2019obtention du Doctorat de l’Institut Polytechnique de Paris, pr\u00e9par\u00e9 \u00e0 T\u00e9l\u00e9com SudParis en :<\/p>\n\n\n\n
le VENDREDI 10 JANVIER 2025 \u00e0 10h00<\/p>\n\n\n\n
\u00e0<\/p>\n\n\n\n
Amphith\u00e9\u00e2tre 4
19 place marguerite perey 91120 palaiseau<\/p>\n\n\n\n
Membres du jury :<\/strong><\/p>\n\n\n\n M. Pierre SUTRA<\/strong>, Professeur, T\u00e9l\u00e9com SudParis, FRANCE – Directeur de these R\u00e9sum\u00e9 :<\/strong><\/p>\n\n\n\n Depuis le milieu des ann\u00e9es 2000, l’augmentation de la fr\u00e9quence des transistors, contrainte par leur capacit\u00e9 \u00e0 dissiper la chaleur produite, a consid\u00e9rablement r\u00e9duit. En r\u00e9ponse, les concepteurs de microprocesseurs ont opt\u00e9 pour des architectures multic\u0153urs. Ainsi, le parall\u00e9lisme est devenu indispensable pour tirer parti des capacit\u00e9s de calcul des machines. Cependant, l\u2019\u00e9criture de programmes parall\u00e8les et concurrents peut \u00eatre complexe, n\u00e9cessitant la gestion des entrelacements des fils d\u2019ex\u00e9cution, du r\u00e9-ordonnancement des t\u00e2ches, ainsi qu\u2019une solide compr\u00e9hension du mod\u00e8le m\u00e9moire sur lequel le programme s’ex\u00e9cute. Pour faciliter la t\u00e2che des d\u00e9veloppeurs, plusieurs biblioth\u00e8ques (par exemple, java.util.concurrent, Boost.LockFree…) proposent des objets concurrents. Ces biblioth\u00e8ques visent \u00e0 r\u00e9pondre aux besoins d’un large \u00e9ventail de cas d’utilisation et, par cons\u00e9quent, les objets qu’elles impl\u00e9mentent sont souvent dot\u00e9s d’interfaces tr\u00e8s fournis, rendant leur impl\u00e9mentation complexe. En particulier, on utilise pour impl\u00e9menter ces objets des m\u00e9canismes tels que les verrous, les barri\u00e8res et les primitives non bloquantes comme \u00ab\u00a0compare-and-swap\u00a0\u00bb, ce qui affecte directement les performances de l’objet. Pour obtenir de meilleures performances, il n’est pas rare que les d\u00e9veloppeurs impl\u00e9mentent des versions \u00ab\u00a0ad-hoc\u00a0\u00bb de ces objets concurrents Nous appelons ces objets les objets ajust\u00e9s. Cette th\u00e8se a pour objectif de jeter les bases th\u00e9oriques et pratiques des objets ajust\u00e9s. Pour ce faire, nous faisons d’abord un \u00e9tat de l’art sur le support de la programmation parall\u00e8le et concurrente. Cet \u00e9tat de l’art est suivi d’une analyse de plusieurs syst\u00e8mes de gestion de donn\u00e9es pour examiner dans quelle mesure l’interface des objets concurrents est utilis\u00e9 par les d\u00e9veloppeurs. Ensuite, nous proposons la premi\u00e8re d\u00e9finition formelle des objets ajust\u00e9s, bas\u00e9e sur un nouvel outil permettant de mesurer la parall\u00e9lisabilit\u00e9 d’un objet concurrent : le graphe d’indistinguabilit\u00e9. Plus loin, nous pr\u00e9sentons une biblioth\u00e8que d’objets ajust\u00e9s nomm\u00e9e DEGO. Cette biblioth\u00e8que inclut plusieurs versions ajust\u00e9es d’objets concurrents usuels, tels que dictionnaire, ensemble, file ou encore compteur. Chaque objet ajust\u00e9 offre une impl\u00e9mentation efficace pour un contexte particulier (par exemple, les op\u00e9rations d’\u00e9criture concurrentes sont toutes commutatives). La derni\u00e8re partie de cette th\u00e8se porte sur l’\u00e9valuation de la biblioth\u00e8que DEGO. Nous comparons les performances des objets ajust\u00e9s \u00e0 ceux de java.util.concurrent en utilisant des micro-benchmarks et une application de type r\u00e9seau social. Abstract :<\/strong><\/p>\n\n\n\n Since the mid-2000s, the increase in transistor frequency has significantly slowed due to limitations in dissipating generated heat. In response, microprocessor designers have shifted towards multicore architectures, making parallelism essential to fully leverage the computing power of modern machines. However, writing parallel and concurrent programs is complex, requiring careful management of thread interleaving, task reordering, and a deep understanding of the memory model on which the program operates. To ease developers\u2019 work, several libraries (e.g., java.util.concurrent, Boost.LockFree…) offer concurrent objects designed to address a wide variety of use cases. Consequently, these objects often feature extensive interfaces, making their implementation complex. Specifically, mechanisms such as locks, barriers, and non-blocking primitives like compare-and-swap are used to implement these objects, which directly impacts their performance. For better performance, developers frequently implement \u00ab\u00a0ad-hoc\u00a0\u00bb versions of these concurrent objects, which we refer to as \u00ab\u00a0adjusted objects\u00a0\u00bb. This thesis aims to establish both the theoretical and practical foundations of adjusted objects. To achieve this, we first present a review of the support for parallel and concurrent programming. This review is followed by an analysis of several data management systems to assess the extent to which concurrent object interfaces are used by developers. Next, we propose the first formal definition of adjusted objects, based on a new tool to measure the parallelizability of a concurrent object: the indistinguishability graph. Further, we introduce a library of adjusted objects named DEGO. This library includes several optimized versions of common concurrent objects, such as dictionaries, sets, queues, and counters. Each adjusted object provides an efficient implementation for a specific context (e.g., all concurrent write operations are commutative). The final part of this thesis focuses on evaluating the DEGO library, comparing the performance of adjusted objects with those in java.util.concurrent using micro-benchmarks and a social network-style application.<\/p>\n","protected":false},"excerpt":{"rendered":" L’Ecole doctorale : Ecole Doctorale de l’Institut Polytechnique de Paris et le Laboratoire de recherche SAMOVAR – Services r\u00e9partis, Architectures, Mod\u00e9lisation, Validation, Administration des R\u00e9seaux pr\u00e9sentent l\u2019AVIS DE SOUTENANCE de Monsieur Boubacar KANE Autoris\u00e9 \u00e0 pr\u00e9senter ses travaux en vue de l\u2019obtention du Doctorat de l’Institut Polytechnique de Paris, pr\u00e9par\u00e9 \u00e0 T\u00e9l\u00e9com SudParis en : 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Mme Vania MARANGOZOVA<\/strong>, Professeure, Universit\u00e9 de Grenoble-Alpes, FRANCE – Rapporteur
M. Davide FREY<\/strong>, Charg\u00e9 de recherche, Universit\u00e9 de Rennes, FRANCE – Rapporteur
M. Julien SOPENA<\/strong>, Ma\u00eetre de conf\u00e9rences, Sorbonne Universit\u00e9, FRANCE – Examinateur
M. Petr KUZNETSOV<\/strong>, Professeur, T\u00e9l\u00e9com Paris, FRANCE – Examinateur
M. Fran\u00e7ois TRAHAY<\/strong>, Professeur, T\u00e9l\u00e9com SudParis, FRANCE – Examinateur<\/p>\n\n\n\n\u00ab Les objets ajust\u00e9s: Une approche bien fond\u00e9e et efficace pour la programmation concurrente \u00bb<\/h2>\n\n\n\n
pr\u00e9sent\u00e9 par Monsieur Boubacar KANE<\/h2>\n\n\n\n
<\/p>\n\n\n\n