enable uploading server cpu usage data from performance tests to big query
diff --git a/tools/run_tests/performance/bq_upload_result.py b/tools/run_tests/performance/bq_upload_result.py
index ddcf053..89d2a9b 100755
--- a/tools/run_tests/performance/bq_upload_result.py
+++ b/tools/run_tests/performance/bq_upload_result.py
@@ -115,9 +115,11 @@
   scenario_result['scenario']['clientConfig'] = json.dumps(scenario_result['scenario']['clientConfig'])
   scenario_result['scenario']['serverConfig'] = json.dumps(scenario_result['scenario']['serverConfig'])
   scenario_result['latencies'] = json.dumps(scenario_result['latencies'])
+  scenario_result['serverCpuStats'] = []
   for stats in scenario_result['serverStats']:
-    stats.pop('totalCpuTime', None)
-    stats.pop('idleCpuTime', None)
+    scenario_result['serverCpuStats'].append(dict())
+    scenario_result['serverCpuStats'][-1]['totalCpuTime'] = stats.pop('totalCpuTime', None)
+    scenario_result['serverCpuStats'][-1]['idleCpuTime'] = stats.pop('idleCpuTime', None)
   for stats in scenario_result['clientStats']:
     stats['latencies'] = json.dumps(stats['latencies'])
     stats.pop('requestResults', None)
@@ -125,7 +127,7 @@
   scenario_result['clientSuccess'] = json.dumps(scenario_result['clientSuccess'])
   scenario_result['serverSuccess'] = json.dumps(scenario_result['serverSuccess'])
   scenario_result['requestResults'] = json.dumps(scenario_result.get('requestResults', []))
-  scenario_result['summary'].pop('serverCpuUsage', None)
+  scenario_result['serverCpuUsage'] = scenario_result['summary'].pop('serverCpuUsage', None)
   scenario_result['summary'].pop('successfulRequestsPerSecond', None)
   scenario_result['summary'].pop('failedRequestsPerSecond', None)