Contents of Glasgow-haskell-users Digest, Vol 17, Issue 8
Keean Schupke
k.schupke at imperial.ac.uk
Tue Jan 18 10:01:27 EST 2005
Jost Berthold wrote:
>
>>
>> execution unit to do something more useful.
>
>
> Yes: the compiler could do a strictness analysis and hopefully (safe
> analysis)
> tell wether "neededList" is needed by "mungeForResult". In the case of
> algebraic data structures (like lists), things get a bit more complex
> (different degrees of strictness);
> Special data-parallel language concepts weave an automatism into the
> data structures they aim at.
> But apparently, the programmer should know very well if this is the case,
> and she may explicitly opt for speculative evaluation, or not.
> Explicit or
> "implemented" (which means in a way automatic): Garbage collection in a
> parallel system is able to detect unneeded results and will stop the
> computation in this case.
>
I wait for the day the compiler does it all for us... One of the reasons
for adopting
Haskell is the way functional languages parallel hardware implementations
(in VHDL recursion = registers ... and parameters = wires). With an
imperative
language all the side effects get in the way (side-effects = memory
access over
a bus).
It seems to me the compiler should sort out all the possible
parallelisations, and
static dependancies, the RTS should deal with dynamic-dependancies and
speculative execution...
It would be nice if the compiler would also calculate a cost metric for
funtions, so
that the RTS could make intelligent architecture dependant decisions on
whether
to run a dependancy sequentially on the current CPU, or in parallel on
another.
But of course to me the beauty is that not one like of source code
should need
to be modified...
Keean.
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