Concurrency and Synchronisation in Actel
Resumo
This paper introduces concurrency mechanisms of a new concurrent object based language called Actel. In particular, it focuses on the issues of how to explore parallel computation with object oriented techniques, how to achieve a good run time efficiency, and how to avoid the burden of explicit synchronisation. Actel offers a variety of inter and intra-object mechanisms to exploit concurrency at several levels of an object. A new mode of message passing called 'semi-reference' is devised to achieve an efficient inter-object communication and to efficiently support inter-object parallelism (coarse grain). The semi-reference allows transmission of references within messages to achieve an eficient delegation whilst preventing inconsistencies. Parallel function are allowed to execute inside an object to achieve medium grain of parallelism without recourse to implicit synchronisation. Finer grain of parallelism can be obtained by activating parallel compound statements inside parallel functions. Multiple future variables (simple or overloaded) are provided to remove the burden of explicit synchronisation, to be the place holder of results from the parallel functions and compound statements and to maximise parallelism.
Referências
America, POOL-T: A Parallel Object Oriented Language, In A. Yonezawa and M. Tokoro, editors, Object Oriented Concurrent Programming, pages 199-220, MIT Press 1987.
Black et al, Object Structure in the Emerald System, In OOPSLA'86, ACM Sigplan Notices, vol 21 (11), pages 60-65.
Caromel, Concurrency: An Object Oriented Approach, In TOOLS PACIFIC'90, Sydney, November 1990.
Chandra et al: COOL: A Language for Parallel Programming, Chapter 8, In Gerlenter et al, 1990.
Elliot and J. Moss, Concurrency Features for the treuillis/Owl Language, In J. bezivin et al, editors, ECOOP'87, Lecture Notes in Computer Science, Springer-Verlag, 1987.
Holliman, C. M. Wang and P. M. Dew, Mistral-3: Parallel Solid Modeling, The Visual Computer for a Special Issue on SuperComputing for Visualisation, 1992.
kafura and K. Lee: Inheritance in an Actor Based Concurrent Object Oriented Programming Languages, In Stephen Cook, editors, ECCOP'89, pages 131-146, Cambridge University Press.
Lieberman, Concurrent Object Oriented Programming in Actl, In A. Yonezawa and M. Tokoro, editors, Object Oriented Concurrent Programming, pages 9-36, MIT Press 1987.
Mallon and P. M. Dew, Communicating through Shared Objects, In Proc of IFIP Conference on Programming Environments for Parallel Computing, Edinburgh 1992.
Theriault, Issues in the Design and Implementation of Act2, Technical Report TR-728, MIT Al Laboratory, 1983.
Yokote and M. Tokoro, Concurrent Programming in Concurrent Smalltalk, In A. Yonezawa and M. Tokoro, editors, Object Oriented Concurrent Programming, pages 129-158, MIT Press 1987.
Yonezawa et al, Object Oriented Concurrent Programming in ABCL/I, In OOPSLA'86, ACM Sigplan Notices, vol 21 (11), pages 258-268.
