[concurrency-interest] Nice video interview with Tim Harris andSimon Peyton-Jones

Joshua Bloch josh at bloch.us
Thu Dec 28 14:14:12 EST 2006


Yes, I think we're in agreement.  I a big fan of STM as a research topic.  I
just don't think it's ready for prime time yet.  In particular, I don't
think we really have a handle on how it will feel to programmers.


On 12/28/06, Brian Goetz <brian at quiotix.com> wrote:
> > Hmmm.  I remember people bitching about GC performance, but not
> > usability.
> I remember people bitching about unreliability, too, though those were
> mostly out of ignorance.  FUD items like pointers hidden from the
> collector (newP = p XOR 0xCAFEBABE; p=0) and cyclical data structures
> that can't be reclaimed by reference counting.
> > I'm saying that the transaction model is not as easy to
> > program to as it appears, and it does not free you from thinking about
> > locks (in my experience with Encina and Camelot).  Did people bitch
> > about the usability of GC?
> A sufficiently large quantitative difference becomes a qualitative
> difference.  If the performance is so poor, you'll do all sorts of
> things to avoid using it, and then its as if you don't have it, and you
> bitch about that.
> People understand "one big fat lock".  People don't use OBFL because
> they are convinced the performance would suck.  If we could make the
> performance of OBFL better, I think many of the usability issues go away
> _relative to the current audience_.
> But, of course, once you make things easier, the audience grows, and the
> new expanded audience might not see the subtleties of "don't do I/O in
> atomic blocks" and things like that.
> I don't want to come off as having drank the kool-aid -- I think there's
> a long way to go before STM is real (though the Azul implementation is a
> nice proof for the concept) -- I just think that many of the arguments
> raised against it are the same as those that have been raised against
> many other fledgling technologies that we've since come to love.  I am
> anxiously hoping the research boys come up with something good here,
> because what we've got now is a bunch of bananas.
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