diff --git a/perf/collector_libpfm.go b/perf/collector_libpfm.go
index 58a00dada5b..58e5bcae46d 100644
--- a/perf/collector_libpfm.go
+++ b/perf/collector_libpfm.go
@@ -199,7 +199,7 @@ func (c *collector) setup() error {
 
 		leaderFileDescriptors, err := c.createLeaderFileDescriptors(group.events, cgroupFd, groupIndex, leaderFileDescriptors)
 		if err != nil {
-			klog.Error(err)
+			klog.Errorf("Cannot count perf event group %v: %v", group.events, err)
 			c.deleteGroup(groupIndex)
 			continue
 		} else {
@@ -232,7 +232,7 @@ func (c *collector) createLeaderFileDescriptors(events []Event, cgroupFd int, gr
 			config := c.createConfigFromRawEvent(customEvent)
 			leaderFileDescriptors, err = c.registerEvent(eventInfo{string(customEvent.Name), config, cgroupFd, groupIndex, isGroupLeader}, leaderFileDescriptors)
 			if err != nil {
-				return nil, fmt.Errorf("cannot to register perf event: %v", err)
+				return nil, fmt.Errorf("cannot register perf event: %v", err)
 			}
 		} else {
 			config, err := c.createConfigFromEvent(event)
@@ -242,7 +242,7 @@ func (c *collector) createLeaderFileDescriptors(events []Event, cgroupFd int, gr
 			}
 			leaderFileDescriptors, err = c.registerEvent(eventInfo{string(event), config, cgroupFd, groupIndex, isGroupLeader}, leaderFileDescriptors)
 			if err != nil {
-				return nil, fmt.Errorf("cannot to register perf event: %v", err)
+				return nil, fmt.Errorf("cannot register perf event: %v", err)
 			}
 			// Clean memory allocated by C code.
 			C.free(unsafe.Pointer(config))
diff --git a/perf/collector_libpfm_test.go b/perf/collector_libpfm_test.go
index 7dbf09f2ed4..c1ef62a836f 100644
--- a/perf/collector_libpfm_test.go
+++ b/perf/collector_libpfm_test.go
@@ -27,8 +27,6 @@ import (
 
 	"golang.org/x/sys/unix"
 
-	"golang.org/x/sys/unix"
-
 	"github.com/stretchr/testify/assert"
 
 	info "github.com/google/cadvisor/info/v1"
diff --git a/perf/uncore_libpfm.go b/perf/uncore_libpfm.go
index 64c50063e7d..18439478edc 100644
--- a/perf/uncore_libpfm.go
+++ b/perf/uncore_libpfm.go
@@ -467,6 +467,7 @@ func (c *uncoreCollector) setupRawEvent(event *CustomEvent, pmus uncorePMUs, gro
 
 	return nil
 }
+
 func (c *uncoreCollector) deleteGroup(groupIndex int) {
 	groupPMUs := c.cpuFiles[groupIndex]
 	for pmu, group := range groupPMUs {