perf stat: Avoid printing cpus with no counters

perf_evlist's user_requested_cpus can contain CPUs not present in any
evsel's cpus, for example uncore counters. Avoid printing the prefix and
trailing \n until the first valid counter is encountered.

Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Alexander Antonov <alexander.antonov@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: German Gomez <german.gomez@arm.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Fastabend <john.fastabend@gmail.com>
Cc: John Garry <john.garry@huawei.com>
Cc: KP Singh <kpsingh@kernel.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Riccardo Mancini <rickyman7@gmail.com>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yonghong Song <yhs@fb.com>
Link: http://lore.kernel.org/lkml/20220503041757.2365696-4-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
index d9629a8..13f7057 100644 (file)
--- a/tools/perf/util/stat-display.c
+++ b/tools/perf/util/stat-display.c
@@ -948,8 +948,6 @@ static void print_no_aggr_metric(struct perf_stat_config *config,
                struct evsel *counter;
                bool first = true;
 
-               if (prefix)
-                       fputs(prefix, config->output);
                evlist__for_each_entry(evlist, counter) {
                        u64 ena, run, val;
                        double uval;
@@ -961,6 +959,8 @@ static void print_no_aggr_metric(struct perf_stat_config *config,
 
                        id = aggr_cpu_id__cpu(cpu, /*data=*/NULL);
                        if (first) {
+                               if (prefix)
+                                       fputs(prefix, config->output);
                                aggr_printout(config, counter, id, 0);
                                first = false;
                        }
@@ -972,7 +972,8 @@ static void print_no_aggr_metric(struct perf_stat_config *config,
                        printout(config, id, 0, counter, uval, prefix,
                                 run, ena, 1.0, &rt_stat);
                }
-               fputc('\n', config->output);
+               if (!first)
+                       fputc('\n', config->output);
        }
 }