Messages in this thread | | | Date | Tue, 5 Jul 2016 14:04:26 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH] perf: fix pmu::filter_match for SW-led groups |
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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.
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