And THAT is the problem
Posted Aug 22, 2011 17:00 UTC (Mon) by khim
In reply to: And THAT is the problem
Parent article: HP dropping webOS devices
> Right. And this is where you experience the most extreme dropouts and slowdowns.
Really? Do you have any data to back this up? Can you cite any measuremeants to that effect?
Ah, now we back to the whole BFS debate. No, I have no benchmarks present. I know how to make Java interface not "extremely sucky" but "kind-of-acceptable" - but yes, it's kind of black magic and I'm not 100% sure all techniques are actually required and proper. The main guide are dropout benchmarks for real programs: you just log timing of operations and tweak the architecture till they show acceptable timings. And I know I never need such black magic for simple, non-GC-driven programs: there I can measure timings without a lot of complicated experiments and be reasonably sure this will translate well to the end product. Not so with GC.
> How will you compact a heap with multimegabyte arrays without significant delays?
I don't know, but that doesn't mean it's not possible. I mean, people have been writing books about GCs (e. g. http://www.amazon.com/dp/0471941484/), do you really expect me to answer this kind of questions in an lwn comment?
Sure. It's typical problems for real programs. And if the best answer you can offer "there are a lot of papers on subject, surely CS wizards solved the problem long ago" then I'm not convinced.
Because these are the same "wizards from Ivory Tower" that proclaimed 20 years ago "Among the people who actually design operating systems, the debate is essentially over. Microkernels have won."
This was nice theory but practice is different. In practice two out of three surviving major OSes are microkernel-based only in name and one is not microkernel at all. I suspect the same will happen with GC: wizards promised that with GC you can just ignore memory issues and concentrate on what you need to do, but in practice it only works for packet computation (things like compilers or background indexers) while in UI you spend so much time fighting GC the whole savings become utterly pointless.
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