perf evsel: Add error message for unsupported branch stack cases

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EOPNOTSUPP is a possible return value when branch stacks are requested
but they aren't enabled in the kernel or hardware. It's also returned if
they aren't supported on the specific event type. The currently printed
error message about sampling/overflow-interrupts is not correct in this
case.

Add a check for branch stacks before sample_period is checked because
sample_period is also set (to the default value) when using branch
stacks.

Before this change (when branch stacks aren't supported):

  perf record -j any
  Error:
  cycles: PMU Hardware doesn't support sampling/overflow-interrupts. Try 'perf stat'

After this change:

  perf record -j any
  Error:
  cycles: PMU Hardware or event type doesn't support branch stack sampling.

Signed-off-by: James Clark <james.clark@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: German Gomez <german.gomez@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20220307171917.2555829-2-james.clark@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

...

This commit is contained in:

James Clark 2022-03-07 17:19:14 +00:00 • committed by Arnaldo Carvalho de Melo

parent 4cee08fbd2

commit 8f431a2869

1 changed files with 4 additions and 0 deletions

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tools/perf/util/evsel.c

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