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perf report: Remove the first overflow check for branch counters

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A false overflow warning is triggered if a sample doesn't have any LBRs
recorded and the branch counters feature is enabled.

The current code does OVERFLOW_CHECK_u64() at the very beginning when
reading the information of branch counters. It assumes that there is at
least one LBR in the PEBS record. But it is a valid case that 0 LBR is
recorded especially in a high context switch.

Remove the OVERFLOW_CHECK_u64(). The later OVERFLOW_CHECK() should be
good enough to check the overflow when reading the information of the
branch counters.

Fixes: 9fbb4b0230 ("perf tools: Add branch counter knob")
Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20240813160208.2493643-3-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Kan Liang 2024-08-13 09:02:01 -07:00 committed by Arnaldo Carvalho de Melo
parent 3ef4445807
commit 183212a45e
1 changed files with 0 additions and 2 deletions
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2
tools/perf/util/evsel.c
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@ -2884,8 +2884,6 @@ int evsel__parse_sample(struct evsel *evsel, union perf_event *event,
array = (void *)array + sz;
if (evsel__has_branch_counters(evsel)) {
OVERFLOW_CHECK_u64(array);
data->branch_stack_cntr = (u64 *)array;
sz = data->branch_stack->nr * sizeof(u64);