Am 07. Nov 2014, 19:30 schrieb Ciaran McCreesh <ciaran.mccre...@googlemail.com>:
> On Fri, 07 Nov 2014 19:11:04 +0100 > Jauhien Piatlicki <jauh...@gentoo.org> wrote: >> Then the same question for you: where can one read about the algorithm >> Paludis uses? > > It's basically a two stage process: simple constraint solving using > value ordering heuristics to enforce "don't do unnecessary work", then > ordering (which is not quite a graph process, and which is not as > simple as a topological sort, because the tree is full of circular > dependencies). > > But the interesting question isn't "what's the algorithm?", it's > "what's the model?". That's where the complexity lies: figuring out how > to turn *DEPEND specifications into constraints is an utter pain, and > it isn't clean or easily understandable. The primary reason is || > dependencies: developers like to write not-really-correct and utterly > unobvious dependency strings rather than asking for new syntax so they > can just say what they mean... Currently, for portage just to decide that nothing has to be done on my machine takes around 1 minute. What is in your opinion the main reason for this? And how can we knock this down to reasonable speed? - Is our dependency model that more complex than the problem resolvers of other package managers for other distributions solve? - Is it the algorithm that is implemented for the dependency model? - Is it its implementation? >> And, again, I have herd (did not try myself) that Paludis is as slow >> as Portage. > > Well, you're not comparing like with like. Paludis with "everything > turned off" does more than Portage with "everything turned on". If all > you're looking for is the wrong answer as fast as possible, there are > easier ways of getting it... The last time I compared the resolver speed of portage and paludis both needed almost the same time. Do you have a speed comparison with a similar feature set of both? (Or, alternatively, the speedup one gains by tuning paludis to be as fast as possible). Best, Matthias
