Merge pull request #2891 from Creatone/creatone/empty-perf-config

Check if there are perf events to gather.

Author: iwankgb

perf/manager_libpfm.go

@@ -48,6 +48,10 @@ func NewManager(configFile string, topology []info.Node) (stats.Manager, error)
 		return nil, fmt.Errorf("unable to parse configuration file %q: %w", configFile, err)
 	}
 
+	if len(config.Core.Events) == 0 && len(config.Uncore.Events) == 0 {
+		return nil, fmt.Errorf("there is no events in config file %q", configFile)
+	}
+
 	onlineCPUs := sysinfo.GetOnlineCPUs(topology)
 
 	cpuToSocket := make(map[int]int)

perf/manager_libpfm_test.go

@@ -26,6 +26,13 @@ import (
 	"github.com/google/cadvisor/stats"
 )
 
+func TestEmptyConfigPassed(t *testing.T) {
+	manager, err := NewManager("testing/perf-no-events.json", []info.Node{})
+
+	assert.NotNil(t, err)
+	assert.Nil(t, manager)
+}
+
 func TestNoConfigFilePassed(t *testing.T) {
 	manager, err := NewManager("", []info.Node{})
 

perf/testing/perf-no-events.json

@@ -0,0 +1,11 @@
+{
+  "core": {
+    "events": [],
+    "custom_events": []
+  },
+  "uncore": {
+    "events": [],
+    "custom_events": []
+  }
+}
+