perf stat: Tidy up JSON metric-only output when no metrics

It printed empty strings for each metric.  I guess it's needed for CSV
output to match the column number.  We could just ignore the empty
metrics in JSON but it ended up with a broken JSON object with a
trailing comma.

So I added a dummy '"metric-value" : "none"' part.  To do that, it
needs to pass struct outstate to print_metric_end() to check if any
metric value is printed or not.

Before:

  # perf stat -aj --metric-only --per-socket --for-each-cgroup system.slice true
  {"socket" : "S0", "cpu-count" : 8, "cgroup" : "system.slice", "" : "", "" : "", "" : "", "" : "", "" : "", "" : "", "" : "", "" : ""}

After:

  # perf stat -aj --metric-only --per-socket --for-each-cgroup system.slice true
  {"socket" : "S0", "cpu-count" : 8, "cgroup" : "system.slice", "metric-value" : "none"}

Signed-off-by: Namhyung Kim <[email protected]>
Acked-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Athira Jajeev <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Xing Zhengjun <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

0 files changed, 0 insertions, 0 deletions