| 1 | Synchronous Programming with User-Level Threads in C∀
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| 2 |
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| 3 | When computations cannot be satisfied immediately, programmers must use
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| 4 | one of two paradigms, Synchronous Programming and Asynchronous Programming.
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| 5 | This presentation discusses the benefits Synchronous Programming over
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| 6 | Asynchronous Programming and what requirements exist to use this paradigm.
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| 7 | It also discusses how C∀, a concurrent and backwards-compatible extension
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| 8 | of the C programming language, has powerful tools available for simple and
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| 9 | efficient Synchronous Programming. These tools include user-level threads
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| 10 | and high-level locking mechanisms which simply solve common problems.
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| 11 | Finally, the presentation shows different techniques to combine these
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| 12 | features with existing code to either uses blocking operations provided by
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| 13 | the kernel or is built according to an asynchronous paradigm.
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| 14 |
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| 15 |
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| 16 |
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| 17 |
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| 18 |
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| 19 |
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| 20 |
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| 21 |
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| 22 |
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| 23 | C∀ is a polymorphic, non-object-oriented, concurrent, backwards-compatible
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| 24 | extension of the C programming language. This paper discusses the design
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| 25 | philosophy and implementation of its advanced control-flow and concurrent/parallel
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| 26 | features, along with the supporting runtime written in C∀. These features
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| 27 | are created from scratch as ISO C has only low-level and/or unimplemented
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| 28 | concurrency, so C programmers continue to rely on library features like pthreads.
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| 29 | C∀ introduces modern language-level control-flow mechanisms, like generators,
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| 30 | coroutines, user-level threading, and monitors for mutual exclusion and
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| 31 | synchronization. The runtime provides significant programmer simplification
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| 32 | and safety by eliminating spurious wakeup and monitor barging. The runtime
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| 33 | also ensures multiple monitors can be safely acquired simultaneously (deadlock free),
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| 34 | and this feature is fully integrated with all monitor synchronization mechanisms.
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| 35 | All control-flow features integrate with the C∀ polymorphic type-system and
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| 36 | exception handling, while respecting the expectations and style of C programmers.
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| 37 | Experimental results show comparable performance of the new features with similar
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| 38 | mechanisms in other concurrent programming languages.
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| 39 | KEYWORDS
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| 40 | generator, coroutine, concurrency, parallelism, thread, monitor, runtime, C, C∀ (Cforall)
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