ParObj : un noyau de système parallèle à objets
François Menneteau · HAL (Le Centre pour la Communication Scientifique Directe) · 1993
The objective of this thesis is to defined the functionalities of a virtual machine called ParObj, that support the notion of concurrent objects, and which is suitable for scalable parallelism. This work is in keeping with the general pattern of the PARX project within the "Massively Parallel System" team of the LGI, which aims at defining and implementing an operating system for parallel machines. By analysing of some known Object-based Distributed System, we extract the basic mechanisms that must be supported within ParObj. We focus our study on the following aspects: entities structures, entities management, interactions between entities management, and resources management. In our approach, we offer within ParObj a parallel support for passive and active objects that can be both large grain (file, process, etc.), and medium grain (linked list, thread, etc.) objects. For an even more subtle management of the parallelism, we support the notion of fragmented objects. On the other hand, we have decided to let compilers handle furthermore fine grain objects. In order to reduce data access conflicts, we provide synchronization mechanism between objects. The general architecture of ParObj is based on the PARX original three level parallel process model: the thread (which is a sequential flow of control within a task), the task (which is an execution context), and the Ptask (which represents a parallel program in execution). A Ptask defines a communication and protection domain, and guarantees the semantic correctness of a parallel program (tasks synchronisation, control of the communication protocols, etc.) Within a Ptask, object protection is enforced through capabilities. Entity localisation (which depends on its visibility and reference) is achieved through an original naming mechanism. The experiments we realised show that this mechanism is perfectly suited for scalable parallelism management.