Messages in this thread | | | Date | Wed, 2 Jun 2010 14:58:30 -0700 | Subject | Re: [linux-pm] [PATCH 0/8] Suspend block api (version 8) | From | Arve Hjønnevåg <> |
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2010/6/2 mark gross <640e9920@gmail.com>: > On Tue, Jun 01, 2010 at 08:50:02PM -0700, Arve Hjønnevåg wrote: >> On Tue, Jun 1, 2010 at 7:05 AM, mark gross <640e9920@gmail.com> wrote: >> > On Tue, Jun 01, 2010 at 09:07:37AM +0200, Florian Mickler wrote: >> ... >> >> +static void update_target_val(int pm_qos_class, s32 val) >> >> +{ >> >> + s32 extreme_value; >> >> + s32 new_value; >> >> + extreme_value = atomic_read(&pm_qos_array[pm_qos_class]->target_value); >> >> + new_value = pm_qos_array[pm_qos_class]->comparitor(val,extreme_value); >> >> + if (extreme_value != new_value) >> >> + atomic_set(&pm_qos_array[pm_qos_class]->target_value,new_value); >> >> +} >> >> + >> > >> > Only works 1/2 the time, but I like the idea! >> > It fails to get the righ answer when constraints are reduced. But, this >> > idea is a good improvement i'll roll into the next pm_qos update! >> > >> >> I think it would be a better idea to track your constraints with a >> sorted data structure. That way you can to better than O(n) for both >> directions. If you have a lot of constraints with the same value, it >> may even be worthwhile to have a two stage structure where for >> instance you use a rbtree for the unique values and list for identical >> constraints. > > I don't agree, we went through this tree vrs list discussion a few times > before in other areas of the kernel. Wherever the list tended to be > short, a simple list wins. However; we can try it, after we have some > metrics and stress test cases identified we can measure its effectivenes > against. >
The list is not short. You have all the inactive and active constraints on the same list. If you change it to a two level list though, the list of unique values (which is the list you have to walk) may be short enough for a tree to be overkill.
-- Arve Hjønnevåg -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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