Skip to main content

Parallel Objects for Multicores: A Glimpse at the Parallel Language Encore

Part of the Lecture Notes in Computer Science book series (LNPSE,volume 9104)

Abstract

The age of multi-core computers is upon us, yet current programming languages, typically designed for single-core computers and adapted post hoc for multi-cores, remain tied to the constraints of a sequential mindset and are thus in many ways inadequate. New programming language designs are required that break away from this old-fashioned mindset. To address this need, we have been developing a new programming language called Encore, in the context of the European Project UpScale. The paper presents a motivation for the Encore language, examples of its main constructs, several larger programs, a formalisation of its core, and a discussion of some future directions our work will take. The work is ongoing and we started more or less from scratch. That means that a lot of work has to be done, but also that we need not be tied to decisions made for sequential language designs. Any design decision can be made in favour of good performance and scalability. For this reason, Encore offers an interesting platform for future exploration into object-oriented parallel programming.

Keywords

  • Method Call
  • Preferential Attachment
  • Active Object
  • Parallel Combinators
  • Data Race

These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Partly funded by the EU project FP7-612985 UpScale: From Inherent Concurrency to Massive Parallelism through Type-based Optimisations (http://www.upscale-project.eu).

This is a preview of subscription content, access via your institution.

Buying options

Chapter
USD   29.95
Price excludes VAT (USA)
  • DOI: 10.1007/978-3-319-18941-3_1
  • Chapter length: 56 pages
  • Instant PDF download
  • Readable on all devices
  • Own it forever
  • Exclusive offer for individuals only
  • Tax calculation will be finalised during checkout
eBook
USD   44.99
Price excludes VAT (USA)
  • ISBN: 978-3-319-18941-3
  • Instant PDF download
  • Readable on all devices
  • Own it forever
  • Exclusive offer for individuals only
  • Tax calculation will be finalised during checkout
Softcover Book
USD   59.99
Price excludes VAT (USA)
Fig. 1.
Fig. 2.
Fig. 3.
Fig. 4.
Fig. 5.
Fig. 6.
Fig. 7.
Fig. 8.
Fig. 9.
Fig. 10.
Fig. 11.
Fig. 12.
Fig. 13.
Fig. 14.
Fig. 15.
Fig. 16.
Fig. 17.
Fig. 18.
Fig. 19.
Fig. 20.
Fig. 21.
Fig. 22.

Notes

  1. 1.

    This design should change, so that await will become more similar to get, but with a different effect on the active object.

  2. 2.

    Ideally, this should be: handler.handle( await fut). Future versions of Encore will support this semantics.

  3. 3.

    An alternative version of Par t is possible where the order in the collection is not preserved. This will be considered in more detail in future experiments.

  4. 4.

    As work in parallel types and combinators is work in progress, this list is likely to change and grow.

  5. 5.

    Relies on Maybe data type: in Haskell syntax data Maybe a = Nothing | Just a. Data types are at present being implemented. An alternative to Maybe is to use Par restricted to empty and singleton collections. With this encoding, the constructors for Maybe become Nothing = empty, Just a = liftv a (from Sect. 9.3), and the destructor, maybe ::

    figure ay

    in Haskell, is defined in Encore as def maybe

    figure az

    .

  6. 6.

    Note that at the time of writing, the capability system has not been fully implemented.

  7. 7.

    Encore may eventually not include all kinds of capabilities presented here, this is a matter under consideration.

  8. 8.

    \(\mu \) Encore supports interfaces, though Encore does not yet. Encore with combine interfaces with traits.

  9. 9.

    In Encore the constructor does not run asynchronously.

References

  1. Agha, G.A.: ACTORS: A Model of Concurrent Computations in Distributed Systems. The MIT Press, Cambridge (1986)

    Google Scholar 

  2. Agha, G.A., Mason, I.A., Smith, S.F., Talcott, C.L.: A foundation for actor computation. J. Funct. Program. 7(1), 1–72 (1997)

    MathSciNet  CrossRef  MATH  Google Scholar 

  3. Albert, R., Barabási, A.-L.: Statistical mechanics of complex networks. Rev. Mod. Phys. 74, 47–97 (2002)

    MathSciNet  CrossRef  MATH  Google Scholar 

  4. Armstrong, J.: Programming Erlang: Software for a Concurrent World. Pragmatic Bookshelf, Raleigh (2007)

    Google Scholar 

  5. Baker Jr., H.C., Hewitt, C.: The incremental garbage collection of processes. SIGPLAN Not. 12(8), 55–59 (1977)

    CrossRef  Google Scholar 

  6. Barabási, A.-L., Albert, R.: Emergence of scaling in random networks. Science 286(5439), 509–512 (1999)

    MathSciNet  CrossRef  MATH  Google Scholar 

  7. Caromel, D., Henrio, L., Serpette, B.P.: Asynchronous sequential processes. Inf. Comput. 207(4), 459–495 (2009)

    MathSciNet  CrossRef  MATH  Google Scholar 

  8. Castegren, E., Wrigstad, T.: Capable: capabilities for scalability. In: IWACO 2014 (2014)

    Google Scholar 

  9. Cavé, V., Zhao, J., Shirako, J., Sarkar, V.: Habanero-Java: the new adventures of old X10. In: Probst, C.W., Wimmer, C. (eds.) Proceedings of the 9th International Conference on Principles and Practice of Programming in Java, PPPJ 2011, pp. 51–61. ACM, Kongens Lyngby, Denmark, 24–26 August 2011

    Google Scholar 

  10. Clarke, D.: Object ownership and containment. Ph.D. thesis, School of Computer Science and Engineering, University of New South Wales, Australia (2002)

    Google Scholar 

  11. Clarke, D., Noble, J., Wrigstad, T. (eds.): Aliasing in Object-Oriented Programming. Types, Analysis and Verification. LNCS, vol. 7850. Springer, Heidelberg (2013)

    Google Scholar 

  12. Clarke, D., Wrigstad, T.: External uniqueness is unique enough. In: Cardelli, L. (ed.) ECOOP 2003. LNCS, vol. 2743, pp. 176–200. Springer, Heidelberg (2003)

    CrossRef  Google Scholar 

  13. Clarke, D., Wrigstad, T., Östlund, J., Johnsen, E.B.: Minimal ownership for active objects. In: Ramalingam, G. (ed.) APLAS 2008. LNCS, vol. 5356, pp. 139–154. Springer, Heidelberg (2008)

    CrossRef  Google Scholar 

  14. Ducasse, S., Nierstrasz, O., Schärli, N., Wuyts, R., Black, A.P.: Traits: a mechanism for fine-grained reuse. ACM Trans. Program. Lang. Syst. 28(2), 331–388 (2006)

    CrossRef  Google Scholar 

  15. Felleisen, M., Hieb, R.: The revised report on the syntactic theories of sequential control and state. Theoret. Comput. Sci. 103(2), 235–271 (1992)

    MathSciNet  CrossRef  MATH  Google Scholar 

  16. Gosling, J., Joy, B., Steele, G., Bracha, G.: The Java(TM) Language Specification, 3rd edn. Addison-Wesley Professional, Reading (2005)

    MATH  Google Scholar 

  17. Haller, P., Odersky, M.: Scala actors: unifying thread-based and event-based programming. Theoret. Comput. Sci. 410(2–3), 202–220 (2009)

    MathSciNet  CrossRef  MATH  Google Scholar 

  18. Halstead Jr., R.H.: Multilisp: a language for concurrent symbolic computation. ACM Trans. Program. Lang. Syst. 7(4), 501–538 (1985)

    CrossRef  MATH  Google Scholar 

  19. Henrio, L., Huet, F., István, Z.: Multi-threaded active objects. In: De Nicola, R., Julien, C. (eds.) COORDINATION 2013. LNCS, vol. 7890, pp. 90–104. Springer, Heidelberg (2013)

    CrossRef  Google Scholar 

  20. Johnsen, E.B., Hähnle, R., Schäfer, J., Schlatte, R., Steffen, M.: ABS: a core language for abstract behavioral specification. In: Aichernig, B.K., de Boer, F.S., Bonsangue, M.M. (eds.) Formal Methods for Components and Objects. LNCS, vol. 6957, pp. 142–164. Springer, Heidelberg (2011)

    CrossRef  Google Scholar 

  21. Johnsen, E.B., Owe, O.: An asynchronous communication model for distributed concurrent objects. Softw. Syst. Model. 6(1), 35–58 (2007)

    CrossRef  Google Scholar 

  22. Kitchin, D., Quark, A., Cook, W., Misra, J.: The Orc programming language. In: Lee, D., Lopes, A., Poetzsch-Heffter, A. (eds.) FMOODS 2009. LNCS, vol. 5522, pp. 1–25. Springer, Heidelberg (2009)

    CrossRef  Google Scholar 

  23. Lavender, R.G., Schmidt, D.C.: Pattern Languages of Program Design 2. Chapter Active Object: An Object Behavioral Pattern for Concurrent Programming. Addison-Wesley Longman Publishing Co., Inc, Boston (1996)

    Google Scholar 

  24. Liskov, B.H., Shrira, L.: Promises: Linguistic support for efficient asynchronous procedure calls in distributed systems. In: Wise, D.S. (ed.) Proceedings of the SIGPLAN Conference on Programming Lanugage Design and Implementation (PLDI 1988), pp. 260–267. ACM, Atlanta, GE, USA (1988)

    Google Scholar 

  25. Meseguer, J.: Conditional rewriting logic as a unified model of concurrency. Theoret. Comput. Sci. 96, 73–155 (1992)

    MathSciNet  CrossRef  MATH  Google Scholar 

  26. Miller, H., Haller, P., Odersky, M.: Spores: a type-based foundation for closures in the age of concurrency and distribution. In: Jones, R. (ed.) ECOOP 2014. LNCS, vol. 8586, pp. 308–333. Springer, Heidelberg (2014)

    Google Scholar 

  27. Miller, M.S.: Robust composition: towards a unified approach to access control and concurrency control. Ph.D. thesis, Johns Hopkins University, Baltimore, Maryland, USA, May 2006

    Google Scholar 

  28. Nielson, F., Nielson, H.R., Hankin, C.: Principles of Program Analysis. Springer, Heidelberg (1999)

    CrossRef  MATH  Google Scholar 

  29. Noble, J., Clarke, D.G., Potter, J.: Object ownership for dynamic alias protection. In: TOOLS Pacific 1999: 32nd International Conference on Technology of Object-Oriented Languages and Systems, pp. 176–187. IEEE Computer Society, Melbourne, Australia, 22–25 November 1999

    Google Scholar 

  30. Peyton Jones, S., et al.: The Haskell 98 language and libraries: the revised report. J. Funct. Program. 13(1), 0–255 (2003)

    MathSciNet  MATH  Google Scholar 

  31. Prokopec, A., Bagwell, P., Rompf, T., Odersky, M.: A Generic parallel collection framework. In: Jeannot, E., Namyst, R., Roman, J. (eds.) Euro-Par 2011, Part II. LNCS, vol. 6853, pp. 136–147. Springer, Heidelberg (2011)

    CrossRef  Google Scholar 

  32. Reppy, J.H.: Concurrent Programming in ML. Cambridge University Press, Cambridge (1999)

    CrossRef  MATH  Google Scholar 

  33. Rossberg, A., Botlan, D.L., Tack, G., Brunklaus, T., Smolka, G.: Alice Through the Looking Glass, Munich, Germany. Trends in Functional Programming, vol. 5, pp. 79–96. Intellect Books, Bristol (2006). ISBN 1-84150144-1

    Google Scholar 

  34. Srinivasan, S., Mycroft, A.: Kilim: Isolation-typed actors for Java. In: Vitek, J. (ed.) ECOOP 2008. LNCS, vol. 5142, pp. 104–128. Springer, Heidelberg (2008)

    CrossRef  Google Scholar 

  35. The Akka Project. Akka (2015). http://akka.io/

  36. Van Roy, P., Haridi, S.: Concepts, Techniques, and Models of Computer Programming. MIT Press, Cambridge (2004)

    Google Scholar 

  37. Welc, A., Jagannathan, S., Hosking, A.: Safe futures for Java. In: Proceedings of the Object Oriented Programming, Systems, Languages, and Applications (OOPSLA 2005), pp. 439–453. ACM Press, New York, NY, USA (2005)

    Google Scholar 

  38. Wrigstad, T., Pizlo, F., Meawad, F., Zhao, L., Vitek, J.: Loci: simple thread-locality for Java. In: Drossopoulou, S. (ed.) ECOOP 2009. LNCS, vol. 5653, pp. 445–469. Springer, Heidelberg (2009)

    CrossRef  Google Scholar 

  39. Yokote, Y., Tokoro, M.: Concurrent programming in ConcurrentSmalltalk. In: Yonezawa, A., Tokoro, M. (eds.) Object-Oriented Concurrent Programming, pp. 129–158. The MIT Press, Cambridge, Mass. (1987)

    Google Scholar 

  40. Yonezawa, A.: ABCL: An Object-Oriented Concurrent System. Series in Computer Systems. The MIT Press, Cambridge (1990)

    Google Scholar 

  41. Yonezawa, A., Briot, J.-P., Shibayama, E:. Object-oriented concurrent programming in ABCL/1. In: Conference on Object-Oriented Programming Systems, Languages and Applications (OOPSLA 1986) (1986). Sigplan Not. 21(11):258–268 (1986)

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Dave Clarke .

Editor information

Editors and Affiliations

A Code for Preferential Attachments

A Code for Preferential Attachments

figure bs
figure bt
figure bu
figure bv

Rights and permissions

Reprints and Permissions

Copyright information

© 2015 Springer International Publishing Switzerland

About this chapter

Cite this chapter

Brandauer, S. et al. (2015). Parallel Objects for Multicores: A Glimpse at the Parallel Language Encore . In: Bernardo, M., Johnsen, E. (eds) Formal Methods for Multicore Programming. SFM 2015. Lecture Notes in Computer Science(), vol 9104. Springer, Cham. https://doi.org/10.1007/978-3-319-18941-3_1

Download citation

  • DOI: https://doi.org/10.1007/978-3-319-18941-3_1

  • Published:

  • Publisher Name: Springer, Cham

  • Print ISBN: 978-3-319-18940-6

  • Online ISBN: 978-3-319-18941-3

  • eBook Packages: Computer ScienceComputer Science (R0)