On Tue, Jan 29, 2008 at 04:53:56PM +0100, Guillaume Chazarain wrote: > I just thought about something to restore low latencies with > FAIR_GROUP_SCHED, but it's possibly utter nonsense, so bear with me > ;-) The idea would be to reverse the trees upside down. The scheduler > would only see tasks (on the leaves) so could apply its interactivity > magic, but the hierarchical groups would be used to compute dynamic > loads for each task according to their position in the tree:
I think this is equivalent to flattening the hierarchy? We discussed this a bit sometime back [1], but one of its weaknesses is providing strong partitioning between groups when it comes to ensuring fairness. Ex: imagine a group which does a fork-bomb. With the flattened tree, it affects other groups more than it would with a 1-level deep hierarchy. Having said that, I would be interested to hear other solutions that maintain this good partitioning b/n groups and still provide good interactivity! 1. http://lkml.org/lkml/2007/5/30/300 > - now: > - we schedule each level of the tree starting from the root > > - with my proposition: > - we schedule tasks like with !FAIR_GROUP_SCHED, but > calc_delta_fair() would traverse the tree starting from the leaves to > compute the dynamic load. -- Regards, vatsa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
