Français Anglais
Accueil Annuaire Plan du site
Home > Research results > Dissertations & habilitations
Research results
Ph.D de

Ph.D
Group : Parallelism

Nouveaux protocoles de tolérance aux pannes pour les applications de calcul haute performance

Starts on 01/10/2008
Advisor : CAPPELLO, Franck

Funding : AM
Affiliation : Université Paris-Sud
Laboratory : LRI

Defended on 06/12/2011, committee :
André Schiper (Rapporteur), Professeur, EPFL
Pierre Sens (Rapporteur), Professeur, Université Paris 6

George Bosilca (Examinateur), Research Assistant and Adjunct Assistant Professor, ICL, Univeristy of Tenessee
Claude Puech (Examinateur), Professeur, Université Paris Sud
Jean-Louis Roch (Examinateur), Maître de Conférences, IMAG
Frédéric Vivien (Examinateur), Directeur de Recherche, INRIA

Marc Snir (Invité), Professeur, University of Illinois at Urbana Champaign

Franck Cappello (Directeur de thèse), Directeur de Recherche, INRIA

Research activities :

Abstract :
With the evolution of parallel computers, the use of fault
tolerance protocols is required. The techniques used must allow to
minimize the impact of failures while providing good failure free perfromances.
Existing fault tolerance protocols force either a global restart (coordinated
checkpointing protocols) or the log of all messages (message logging protocols)
and thus they are not adapted to these architectures.

We studied the characteristics of the existing protocols. We first studied the
determinism of the applications, since existing protocols assume non deterministic
executions (checkpointing protocols) or piecewise deterministic ones (message
logging protocols). In our study, we focused on the message passing model, and more
specifically on MPI applications. We have analyzed 26 MPI applications and
highlighted a new characteristic called "send-determinism" which corresponds to
most studied applications. In a second step, we focused on the communication
patterns of the applications to study the existence of clusters of processes in
these patterns. The study showed that for most applications, it is possible to
create clusters of processes to minimize the size of clusters and the volume of
inter-cluster messages.

Then we designed two fault tolérance protocols. The first one is an uncoordinated
checkpointing protocol which is based on the send-deterministic assumption and
avoids domino effect while logging only a subset of the application messages. We
have also adapted the protocol to clusters of processes. Then, we proposed HydEE,
a hierarchical protocol that is also based on the send-deterministic assumption and
that is used on clusters of processes. It combines a coordinated checkpointing
protocol inside clusters to a message logging protocol for inter-cluster
messages. Both protocols have been implemented in MPICH2 library and the
performance evaluation showed that they both have a low impact on the
applications failure free performances.

Ph.D. dissertations & Faculty habilitations
APPRENTISSAGE ET OPTIMISATION SUR LES GRAPHES


ANALYSE DE DONNéES MULTI-MODALES POUR LES PATHOLOGIES COMPLEXES PAR LA CONCEPTION ET L’IMPLéMENTATION DE PROTOCOLES REPRODUCTIBLES ET RéUTILISABLES


DESIGNING INTERACTIVE TOOLS FOR CREATORS AND CREATIVE WORK
Creative work has been at the core of research in Human-Computer Interaction (HCI). I describe the results of a series of studies that look at how creators work, where creators include artists with years of professional practice, as well as learners, or novices and casual makers. My research focuses on three creation activities: drawing, physical modeling, and music composition. For these activities, I examine how artists switch between representations and how these representations evolve throughout their creative process, from early sketches to fine-grained forms or structured vocabularies. I present interactive systems that enrich their workflow (i) by extending their computer tools with physical user interfaces, or (ii) by making physical materials interactive. I also argue that sketch-based representations can allow for user interfaces that are more personal and less rigid. My presentation will reflect on lessons and limitations of this work and discuss challenges for future design-support tools.