This short note is the result of a French " Hippocampe internship " 2 that aims at introducing the world of research to young undergraduate French students. The problem studied is the following: imagine yourself locked in a cage barred with n different locks. You are given a keyring with N ≥ n keys containing the n keys that open the locks. In average, how many trials are required to open all l...

Concurrent programming languages have become more popular with the advent of multi-core systems. Shared memory is read or written atomically, by concurrent processes to prevent races. A typical mechanism is the use of locks. However, if locks are not acquired and released in the correct order, the result is a deadlock. In this paper, we propose a deadlock detection tool for a deterministic, con...

This outline describes a special issue of papers from the 2013 workshop on Java Technologies for Real-Time and Embedded Systems [1]. There are 2 papers in this special issue. The first paper [2] discusses software locking mechanisms that commonly protect shared resources for multithreaded applications. This mechanism can, especially in chip-multiprocessor systems, result in a large synchronizat...

The aim of this thesis is to present novel techniques for reasoning about the dynamic and static semantics of concurrent programs that use locks and transactions to isolate accesses to shared memory. We use moverness to characterise the observational semantics of reads issued by locks and transactions under the simpler semantics of free, left, right and both movers. The second contribution is g...

Atomic operations are a key primitive in parallel computing systems. The standard implementation mechanism for atomic operations uses mutual exclusion locks. In an object-based programming system the natural granularity is to give each object its own lock. Each operation can then make its execution atomic by acquiring and releasing the lock for the object that it accesses. But this ne lock gran...

The exibility of nested transactions is generally provided at the expense of a more complex locking mechanism which must deal with expensive lock inheritance. In this paper, we give a solution for eecient lock inheritance. Our solution does not change the original nested transactions model but does revisit its locking rules using set-oriented semantics. This allows us to trade the cost of lock ...

The OpenMP specification lacks a composable shared memory concurrency mechanism: the current OpenMP concurrency mechanisms, such as OMP critical, locks, or atomics, do not support composition. In this paper, we motivate the need for transactional memory (TM) in OpenMP. The chief reason is to support composition of realistic programs, but we also consider whether TM is easier to program than loc...

Concurrency control is mostly based on locks and is therefore notoriously difficult to use. Even though some programming languages provide high-level constructs, these add complexity and potentially hard-to-detect bugs to the application. Transactional memory is an attractive mechanism that does not have the drawbacks of locks, however the underlying implementation is often difficult to integra...