Commit 183212a4 authored by Kan Liang's avatar Kan Liang Committed by Arnaldo Carvalho de Melo
Browse files

perf report: Remove the first overflow check for branch counters 



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: 9fbb4b02 ("perf tools: Add branch counter knob")
Reviewed-by: default avatarAndi Kleen <ak@linux.intel.com>
Signed-off-by: default avatarKan Liang <kan.liang@linux.intel.com>
Acked-by: default avatarNamhyung 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: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 3ef44458

tools/perf/util/evsel.c

+0 −2
Original line number Diff line number Diff line
@@ -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);