[plt-scheme] Futures!

From: Robby Findler (robby at eecs.northwestern.edu)
Date: Mon Apr 12 20:12:40 EDT 2010

Display is not future safe. (You saw the section in the guide right?
That would have helped you understand your code.)


On Monday, April 12, 2010, Synx <plt at synx.us.to> wrote:
> Wow, use of multiple processors? I'll be interested to see where this is
> going! I'm a little confused though. I know currently you have to do a
> lot of fixnum wangdoodles to get it to consider the procedure of the
> future to be "safe" and not "freeze" (thereby serializing any
> parallelization), but even with that I can't seem to get futures to show
> any demonstrable difference on my machine. I made sure to compile with
> --enable-futures, and I'm just on x86_64 Linux so there shouldn't be any
> compatability problems.
> I have two CPUs, so doing a lengthy operation with two futures should be
> (somewhat less than) half as fast as doing the lengthy operation twice.
> So I had hoped that the following script would behave in that fashion.
> Unfortunately, futures don't seem to make even the slightest bit of
> difference in the time it takes to execute the program. Is it that I am
> in a multi-process environment, and it just can't spare more than one
> processor at a time for each of the two futures? Or am I doing something
> wrong?

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