Messages in this thread | | | Date | Fri, 8 May 2020 19:40:19 -0700 | From | Andi Kleen <> | Subject | Re: [RFC PATCH v3 12/14] perf metricgroup: order event groups by size |
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> > I'm not sure if size is that great an heuristic. The dedup algorithm should > > work in any case even if you don't order by size, right? > > Consider two metrics: > - metric 1 with events {A,B} > - metric 2 with events {A,B,C,D} > If the list isn't sorted then as the matching takes the first group > with all the events, metric 1 will match {A,B} and metric 2 {A,B,C,D}. > If the order is sorted to {A,B,C,D},{A,B} then metric 1 matches within > the {A,B,C,D} group as does metric 2. The events in metric 1 aren't > used and are removed.
Ok. It's better for the longer metric if they stay together.
> > The dedup algorithm is very naive :-)
I guess what matters is that it gives reasonable results on the current metrics. I assume it does?
How much deduping is happening if you run all metrics?
For toplev on my long term todo list was to compare it against a hopefully better schedule generated by or-tools, but I never got around to coding that up.
-Andi
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