what is needed is a language-based model of computation in which we assign costs to the steps of the program we actually write, not the one it (allegedly) compiles into. Moreover, in the parallel setting we wish to think in terms of dependencies among computations, rather than the exact order in which they are to be executed. This allows us to factor out the properties of the target platform, such as the number, p, of processing units available, and instead write the program in an intrinsically parallel manner, and let the compiler and run-time system (that is, the semantics of the language) sort out how to schedule it onto a parallel fabric.
Just as abstract languages allow us to think in terms of data structures such as trees or lists as forms of value and not bother about how to “schedule” the data structure into a sequence of words in memory, so a parallel language should allow us to think in terms of the dependencies among the phases of a large computation and not bother about how to schedule the workload onto processors. Storage management is to abstract values as scheduling is to deterministic parallelism.
(Cross-posted @ cloud computing)