From: Glenn Parker Date: 2005-04-11T21:56:28+09:00 Subject: Re: Seven new VMs, all in a row flaig@sanctacaris.net wrote: > I think the "wal-mart argument" is quite an important one. I'm not sure exactly what the "wal-mart argument" is. Wal-Mart can be seen as a big U.S. conglomerate that moves into a town and drives all the mom-and-pop stores out of business, eventually drying up downtown business districts. Or it can be seen as a big discount retailer that provides cheap imported goods using its massive warehousing and distribution networks, while undercutting domestic manufacturers. Obviously, I'm not a big Wal-Mart fan, but maybe their brutal retail success strategy has lessons for Ruby? :) > Apart from explicitly creating threads, it would be nice if > the Ruby system could be taught to automatically recognize > parallelizable code and optimally distribute it across a > multiprocessor system -- implicitly. That would be a big > advange for high-level programming in general! I do not know > the state of the art in this, I only remember that the > Atari/Inmos guys failed do do this in Occam, back in the 1980s. > Do you think there is a serious chance to get such a thing working? The only programming environment I'm familiar with where somebody implemented automatic parallel optimization is Fortran (although I'm sure there are others). Fortran's branching and memory models are constrained enough to allow for some clever analysis. Loops where each iteration has no impact on the next can be discovered and converted into short-term fine-grained parallel execution. In that case, the original code has no concept of threading, it just runs faster during the inner loops. None of that would carry over to a thread-aware language with a dynamic type system. Ilmari Heikkinen wrote: > Re: green threads vs native threads, if a green threads implementation > is 30 times faster, that's like having 29 extra cpus, no? "You can't get blood from a stone." The only thing that is "like having 29 extra cpus" is actually having 29 extra CPUs. :) -- Glenn Parker | glenn.parker-AT-comcast.net |