Messages in this thread | | | From | Alexander Shishkin <> | Subject | Re: [PATCH v6 1/3] perf/core: use rb trees for pinned/flexible groups | Date | Tue, 29 Aug 2017 16:51:53 +0300 |
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Alexey Budankov <alexey.budankov@linux.intel.com> writes:
> Now I figured that not all indexed events are always located under > the root with the same cpu, and it depends on the order of insertion > e.g. with insertion order 01,02,03,14,15,16 we get this: > > 02 > / \ > 01 14 > / \ > 03 15 > \ > 16 > > and it is unclear how to iterate cpu==0 part of tree in this case.
Using this example, rb_next() should take you through the nodes in this order (assuming you start with 01): 01, 02, 03, 14, etc. So you iterate while event->cpu==cpu using rb_next() and you should be fine.
> Iterating cpu specific subtree like this: > > #define for_each_group_event(event, group, cpu, pmu, field) \ > for (event = rb_entry_safe(group_first(group, cpu, pmu), \ > typeof(*event), field); \ > event && event->cpu == cpu && event->pmu == pmu; \ > event = rb_entry_safe(rb_next(&event->field), \ > typeof(*event), field))
Afaict, this assumes that you are also ordering on event->pmu, which should be reflected in your _less function. And also assuming that group_first() is doing the right thing. Can we see the code?
Regards, -- Alex
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