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 <namhyung@kernel.org>
1 file changed
