Personne

Rachid Guerraoui

Publications associées (292)

Software Transactional Memory on Relaxed Memory Models

Pseudo-code descriptions of STMs assume sequentially consistent program execution and atomicity of high-level STM operations like read, write, and commit. These assumptions are often violated in realistic settings, as STM implementations run on relaxed mem ...

Springer2009

The Theory of Transactional Memory

Rachid Guerraoui, Michal Kapalka

Transactional memory (TM) is a promising paradigm for concurrent programming. This paper is an overview of our recent work on defining a theory of TM. We first present a correctness condition of a TM, ensured by most existing TM implementations. Then, we d ...

2009

Names Trump Malice: Tiny Mobile Agents Can Tolerate Byzantine Failures

Rachid Guerraoui, Eric Ruppert

We introduce a new theoretical model of ad hoc mobile computing in which agents have severely restricted memory, highly unpredictable movement and no initial knowledge of the system. Each agent’s memory can store O(1) bits, plus a unique identiﬁer, and O(1 ...

2009

On the weakest failure detector ever

Rachid Guerraoui

Many problems in distributed computing are impossible to solve when no information about process failures is available. It is common to ask what information about failures is necessary and sufficient to circumvent some specific impossibility, e. g., consen ...

Springer Verlag2009

Stretching Transactional Memory

Rachid Guerraoui, Michal Kapalka, Aleksandar Dragojevic

Transactional memory (TM) is an appealing abstraction for programming multi-core systems. Potential target applications for TM, such as business software and video games, are likely to involve complex data structures and large transactions, requiring speci ...

2009

Stretching Gossip with Live Streaming

Rachid Guerraoui, Maxime Monod, Anne-Marie Kermarrec, Davide Frey

Gossip-based information dissemination protocols are considered easy to deploy, scalable and resilient to network dynamics. They are also considered highly ﬂexible, namely tunable at will to increase their robustness and adapt to churn. So far however, the ...

2009

Reliable Distributed Storage

Rachid Guerraoui, Marko Vukolic

Storage is nowadays commonly provided as a service, accessed by clients over a network. A distributed storage service provides clients with the abstraction of a single reliable shared storage device, using a collection of possibly unreliable computing unit ...

2009

Interference-Resilient Information Exchange

Rachid Guerraoui, Seth Gilbert

This paper presents an efficient protocol for reliably exchanging information in a single-hop, multi-channel radio network subject to unpredictable interference. We model the interference by an adversary that can simultaneously disrupt up to t of the C ava ...

Ieee Service Center, 445 Hoes Lane, Po Box 1331, Piscataway, Nj 08855-1331 Usa2009

A Topological Treatment of Early-Deciding Set-Agreement

Rachid Guerraoui, Bastian Pochon

The k-set-agreement problem consists for a set of n processes to agree on less than k among n possibly different Values, each initially known to only one process. The problem is at the heart of distributed computing and generalizes the celebrated consensus ...

2009

Preventing versus Curing: Avoiding Conflicts in Transactional Memories

Rachid Guerraoui, Vasu Singh, Aleksandar Dragojevic

Transactional memories are typically speculative and rely on contention managers to cure conflicts. This paper explores a complementary approach that prevents conflicts by scheduling transactions according to predictions on their access sets. We first expl ...

2009

On Tracking Freeriders in Gossip Protocols

Rachid Guerraoui, Maxime Monod, Anne-Marie Kermarrec, Kévin Clément Huguenin

Peer-to-peer content dissemination applications suffer immensely from freeriders, i.e., nodes that do not provide their fair share. The Tit-for-Tat (TfT) incentives have received much attention as they help make such systems more robust against freeriding. ...

2009

The gap in circumventing the impossibility of consensus

Rachid Guerraoui

The impossibility of reaching deterministic consensus in an asynchronous and crash prone system was established for a weak variant of the problem, usually called weak consensus, where a set of processes need to decide on a common value in {0, 1}, so that b ...

2008

Extensible Encoding of Type Hierarchies

Rachid Guerraoui, Seth Gilbert

2008

The Weakest Failure Detectors to Boost Obstruction-Freedom

Rachid Guerraoui, Michal Kapalka

It is considered good practice in concurrent computing to devise shared object implementations that ensure a minimal obstruction-free progress property and delegate the task of boosting liveness to independent generic oracles called contention managers. Th ...

2008

Secure Communication Over Radio Channels

Rachid Guerraoui, Seth Gilbert

We study the problem of secure communication in a multi-channel, single-hop radio network with a malicious adversary that can cause collisions and spoof messages. We assume no pre-shared secrets or trusted-third-party infrastructure. The main contribution ...

2008

Permissiveness in Transactional Memories

Rachid Guerraoui, Vasu Singh

We introduce the notion of permissiveness in transactional memories (TM). Intuitively, a TM is permissive if it never aborts a transaction when it need not. More specifically, a TM is permissive with respect to a safety property p if the TM accepts every h ...

2008

Failure detectors as type boosters

Rachid Guerraoui

The power of an object type T can be measured as the maximum number n of processes that can solve consensus using only objects of T and registers. This number, denoted cons(T), is called the consensus power of T. This paper addresses the question of the we ...

Springer-Verlag2008

Completeness and Nondeterminism in Model Checking Transactional Memories

Rachid Guerraoui, Vasu Singh

Software transactional memory (STM) offers a disciplined concurrent programming model for exploiting the parallelism of modern processor architectures. This paper presents the first \emph{deterministic} specification automata for strict serializability and ...

Springer2008

A General Characterization of Indulgence

Rachid Guerraoui

An indulgent algorithm is a distributed algorithm that, besides tolerating process failures, also tolerates unreliable information about the interleaving of the processes. This article presents a general characterization of indulgence in an abstract comput ...

2008

The Weakest Failure Detector for Message Passing Set-Agreement

Rachid Guerraoui

In the set-agreement problem, n processes seek to agree on at most n−1 different values. This paper determines the weakest failure detector to solve this problem in a message-passing system where processes may fail by crashing. This failure detector, calle ...

2008