[PATCH 2/9] perf report: Remove the first overflow check for branch counters

kan.liang
2024-07-03T20:03:25Z

From: Kan Liang <kan.liang@linux.intel.com>

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: 9fbb4b02302b ("perf tools: Add branch counter knob")
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
---
tools/perf/util/evsel.c | 2 --
1 file changed, 2 deletions(-)

diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index bc603193c477..a5dd031c9080 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -2810,8 +2810,6 @@ 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);

--
2.38.1