perf report: Fix --total-cycles --stdio output error

The --total-cycles may output wrong information with the --stdio.

For example:

  # perf record -e "{cycles,instructions}",cache-misses -b sleep 1
  # perf report --total-cycles --stdio

The total cycles output of {cycles,instructions} and cache-misses are
almost the same.

  # Samples: 938  of events 'anon group { cycles, instructions }'
  # Event count (approx.): 938
  #
  # Sampled Cycles%  Sampled Cycles  Avg Cycles%  Avg Cycles  [Program Block Range]
  # ...............  ..............  ...........  ..........  ..................................................>
  #
            11.19%            2.6K        0.10%           21  [perf_iterate_ctx+48 -> >
             5.79%            1.4K        0.45%           97  [__intel_pmu_enable_all.constprop.0+80 -> __intel_>
             5.11%            1.2K        0.33%           71  [native_write_msr+0 ->>

  # Samples: 293  of event 'cache-misses'
  # Event count (approx.): 293
  #
  # Sampled Cycles%  Sampled Cycles  Avg Cycles%  Avg Cycles  [Program Block Range]
  # ...............  ..............  ...........  ..........  ..................................................>
  #
            11.19%            2.6K        0.13%           21  [perf_iterate_ctx+48 -> >
             5.79%            1.4K        0.59%           97  [__intel_pmu_enable_all.constprop.0+80 -> __intel_>
             5.11%            1.2K        0.43%           71  [native_write_msr+0 ->>

With the symbol_conf.event_group, the 'perf report' should only report the
block information of the leader event in a group.

However, the current implementation retrieves the next event's block
information, rather than the next group leader's block information.

Make sure the index is updated even if the event is skipped.

With the patch,

  # Samples: 293  of event 'cache-misses'
  # Event count (approx.): 293
  #
  # Sampled Cycles%  Sampled Cycles  Avg Cycles%  Avg Cycles  [Program Block Range]
  # ...............  ..............  ...........  ..........  ..................................................>
  #
           37.98%            9.0K        4.05%           299  [perf_event_addr_filters_exec+0 -> perf_event_a>
           11.19%            2.6K        0.28%            21  [perf_iterate_ctx+48 -> >
            5.79%            1.4K        1.32%            97  [__intel_pmu_enable_all.constprop.0+80 -> __intel_>

Fixes: 6f7164fa231a5f36 ("perf report: Sort by sampled cycles percent per block for stdio")
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: Jin Yao <yao.jin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: https://lore.kernel.org/r/20240813160208.2493643-2-kan.liang@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index dfb47fa85e5c..04b9a5c1bc7e 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -565,6 +565,7 @@ static int evlist__tty_browse_hists(struct evlist *evlist, struct report *rep, c
 		struct hists *hists = evsel__hists(pos);
 		const char *evname = evsel__name(pos);
 
+		i++;
 		if (symbol_conf.event_group && !evsel__is_group_leader(pos))
 			continue;
 
@@ -574,7 +575,7 @@ static int evlist__tty_browse_hists(struct evlist *evlist, struct report *rep, c
 		hists__fprintf_nr_sample_events(hists, rep, evname, stdout);
 
 		if (rep->total_cycles_mode) {
-			report__browse_block_hists(&rep->block_reports[i++].hist,
+			report__browse_block_hists(&rep->block_reports[i - 1].hist,
 						   rep->min_percent, pos, NULL);
 			continue;
 		}