On Sep 24, 2007, at 5:22 PM, Richard Smith wrote: > I would certainly hope that Data Parallelism is a major rewhacking > of the > programming model...we desperately need one. A big challenge is to > find ways of > ...
Of course there's the old Halting vs. Starting problem. In CS theory, the Halting problem is hard (insoluable ;>). But in practice it's easy. Remove power. Take a crowbar to the CPU and similar logic elements. Raddiate the DRAM, etc. Eventually, the system will halt (and typically quite soon after all power is shorted, over-voltage applied, etc.). In computer reality, it's getting a new platform going that's really hard (ISA, OS, etc.) as apps go after volume, etc. > I also think its a reasonable evolutionary step to provide an API > to existing > languages that extends their capabilities, in effect constructing a > new Virtual Except where the new model is so alien to the old one. Where I think the next big leap can most profitably occur is by having a really smooth *calling* relationship between the conventional languages of today and some new data parallel language (and god help anyone who wants to use Verilog and it's PLI as a model!). But if the overall program flow could be maintained, the folks with computationally intense localized (to a procedure/subroutine nest) could dabble in the new technology via conventional linkage ... as long as the new language/environment can work on the data largely in-place and invisibly). > ....sed around Fortran or C than Parallel Haskell. [...even if I > have argued > for years of the value of using functional programming models and > implicit > parallelism, with serial programming as a special case.] While true, it's quite limiting to things with a lot of coarse objects ... and with many threads per chip, I think finer grained approaches are apt to give us the most benefit (and, of course, people working on mega scale multi-petaflops are probably going to mix, fine grain, and MPI (very coarse) grain to completely exploit their machines). It will be very painful, but I don't think they have any choice (and some of them have started to admit it ;>). Keith H. Bierman keith.bierman at Sun.COM | khbkhb at gmail.com Strategic Engagement Team | AIM: kbiermank <speaking for myself, not Sun*> Copyright 2007
