print_metric_only_json and print_metric_end in stat-display.c may
create a metric value of "none" which fails validation as isfloat. Add
a helper to properly validate metric numeric values.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/tests/shell/lib/perf_json_output_lint.py | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/tools/perf/tests/shell/lib/perf_json_output_lint.py b/tools/perf/tests/shell/lib/perf_json_output_lint.py
index c6750ef06c0f..ff90c23d1d62 100644
--- a/tools/perf/tests/shell/lib/perf_json_output_lint.py
+++ b/tools/perf/tests/shell/lib/perf_json_output_lint.py
@@ -43,6 +43,9 @@ def isint(num):
 def is_counter_value(num):
   return isfloat(num) or num == '<not counted>' or num == '<not supported>'
 
+def is_metric_value(num):
+  return isfloat(num) or num == 'none'
+
 def check_json_output(expected_items):
   checks = {
       'counters': lambda x: isfloat(x),
@@ -57,7 +60,7 @@ def check_json_output(expected_items):
       'event-runtime': lambda x: isfloat(x),
       'interval': lambda x: isfloat(x),
       'metric-unit': lambda x: True,
-      'metric-value': lambda x: isfloat(x),
+      'metric-value': lambda x: is_metric_value(x),
       'metric-threshold': lambda x: x in ['unknown', 'good', 'less good', 'nearly bad', 'bad'],
       'metricgroup': lambda x: True,
       'node': lambda x: True,
@@ -65,7 +68,7 @@ def check_json_output(expected_items):
       'socket': lambda x: True,
       'thread': lambda x: True,
       'unit': lambda x: True,
-      'insn per cycle': lambda x: isfloat(x),
+      'insn per cycle': lambda x: is_metric_value(x),
       'GHz': lambda x: True,  # FIXME: it seems unintended for --metric-only
   }
   input = '[\n' + ','.join(Lines) + '\n]'
-- 
2.51.0.384.g4c02a37b29-goog