Messages in this thread | | | Date | Tue, 8 Feb 2022 15:58:55 +0000 | Subject | Re: [RFC PATCH v2 0/5] topdown with metrics | From | Andrew Kilroy <> |
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On 27/01/2022 11:42, Andrew Kilroy wrote: > > > On 20/01/2022 09:26, John Garry wrote: >> On 11/01/2022 15:07, Andrew Kilroy wrote: >>> This patch series adds the ability for the --topdown option to use >>> metrics (defined in json files in the pmu-events directory) to describe >>> how to calculate and determine the output columns for topdown level 1. >>> >>> For this to work, a number of metrics have to be defined for the >>> relevant processor with the MetricGroup name "TopDownL1". perf will >>> arrange for the events defined in each metric to be collected, and each >>> metric will be displayed in the output, as if >>> >>> perf stat -M 'TopDownL1' --metric-only -- exampleapp >>> >>> had been used. >>> >>> Topdown was already implemented where certain kernel events are defined. >>> If these kernel events are defined, the new json metrics behaviour is >>> not used. The json metrics approach is only used if the kernel events >>> are absent. >>> >>> The last patch in the series disables the json metrics behaviour on x86. >>> This is because of concerns that due to SMT it's not straightforward to >>> express the various formulas as json for certain x86 cpus. See >> >> I suppose this solution is ok. >> > > Thanks, would you mind giving it a Reviewed-By? > >> A concern is that today we only have 1x arm64 platform which actually >> supports this in mainline. >> >> Do you have any more which you plan to support? >> > > The Neoverse cores, mainly. >
Thanks for the feedback on this RFC, I think we'll resubmit these patches at a later time, when we've got a json metrics file or two.
Thanks, Andrew
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