Messages in this thread | | | Date | Tue, 5 Jul 2016 13:52:27 +0100 | From | Mark Rutland <> | Subject | Re: [PATCH] perf: fix pmu::filter_match for SW-led groups |
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On Tue, Jul 05, 2016 at 02:04:26PM +0200, Peter Zijlstra wrote: > On Tue, Jul 05, 2016 at 10:44:48AM +0100, Mark Rutland wrote: > > My bad; I assumed that for both PMUs we'd start at the root, and thus > > would need to re-sort in order to get the current CPU's PMU ordered > > first, much like currently with rotation. > > > > I guess I'm having difficulty figuring out the structure of that tree. > > If we can easily/cheaply find the relevant sub-tree then the above isn't > > an issue. > > struct event { > struct rb_node node; > int pmu_id; > s64 lag; > ... > }; > > bool event_less(struct rb_node *a, struct rb_node *b) > { > struct event *left = rb_entry(a, struct event, node); > struct event *right = rb_entry(b, struct event, node); > > if (a->pmu_id < b->pmu_id) > return true; > > if (b->pmu_id > a->pmu_id) > return false; > > /* a->pmu_id == b->pmu_id */ > if (a->lag < b->lag) > return true; > > return false; > } > > Will give you a tree with primary order @pmu_id and secondary order > @lag. > > Which you'd iterate like: > > for (event = event_find(pmu_id); event->pmu_id == pmu_id; event = event_next(event)) { > } > > And get only the events matching @pmu_id in @lag order.
Cheers! Sorry for being thick; I think I understand now.
I'll have a tinker with the idea.
Thanks, Mark.
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