[Haskell-cafe] Dynamic thread management?

Hugh Perkins hughperkins at gmail.com
Mon Sep 17 23:09:53 EDT 2007

Couple of thoughts/observations:

- Erlang has a vm, so that would avoid building a vm.

On the downside, erlang is not pure: the message-passing and the io:
commands imply the possibility of side-effects.

Still, it could be good enough for a proof-of-concept?

- implementation as a library function?

Instead of building/modifying a vm to re-implement how map works,
perhaps an easy way of doing this would be to create a new map
function (dpmap? (=Dynamic parallel map), which chats to a scheduler
process, which decides whether to split the map or not.

Downside: constant overhead for all maps, even really small ones that
would otherwise run really fast, and will ultimately be assigned only
a single process anyway.

(note: using erlang terminology here, where "process" means
essentially "thread").

Of course, even modifying the vm to parallelize maps etc would have a
constant overhead, but possibly the overhead could be much smaller if
implemented directly in a vm?

Possibly an approach could be:
- impliment as a new dpmap library function
- someone could optimize this in a vm later

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