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SubjectRe: [RFC PATCH 1/1] perf arm64: Implement --topdown with metrics
On 14/12/2021 18:42, Andrew Kilroy wrote:
> This patch implements the --topdown option by making use of metrics to
> dictate what counters are obtained in order to show the various topdown
> columns, e.g. Frontend Bound, Backend Bound, Retiring and Bad
> Speculation.
> The MetricGroup name is used to identify which set of metrics are to be
> shown. For the moment use TopDownL1 and enable for arm64
> Signed-off-by: Andrew Kilroy<>

This works in that it gives results, but does not supply the same output
format as for x86 nor has same restrictions in usage (-a commandline
required, for example, below).

For my x86 broadwell:

john@localhost:~/linux/tools/perf> sudo ./perf stat --topdown sleep 1
top down event configuration requires system-wide mode (-a)

john@localhost:~/linux/tools/perf> sudo ./perf stat --topdown -a sleep 1
Performance counter stats for 'system wide':

retiring bad speculation
frontend bound backend bound
S0-D0-C0 2 29.2% 6.3%
37.4% 27.1%
S0-D0-C1 2 20.4% 6.2%
42.1% 31.3%

0.998007338 seconds time elapsed



Then my arm64 hip08 platform:

john@debian:~/kernel-dev/tools/perf$ sudo ./perf stat --topdown sleep 1

Performance counter stats for 'sleep 1':

retiring bad_speculation backend_bound
0.19 0.17 0.27

1.000832714 seconds time elapsed

0.000891000 seconds user
0.000000000 seconds sys

And there is no colouring for results which are above/below standard
thresholds (see stat-shadow.c:get_radio_color()).

My impression is that we're not plugging the results from
metricgroup__parse_groups_to_evlist() into the --topdown print
functionality properly.


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