diff --git a/core/conf/time.go b/core/conf/time.go
deleted file mode 100644
index be47300c..00000000
--- a/core/conf/time.go
+++ /dev/null
@@ -1,16 +0,0 @@
-package conf
-
-import "time"
-
-const minDuration = 100 * time.Microsecond
-
-// CheckedDuration returns the duration that guaranteed to be greater than 100us.
-// Why we need this is because users sometimes intend to use 500 to represent 500ms.
-// In config, duration less than 100us should always be missing ms etc.
-func CheckedDuration(duration time.Duration) time.Duration {
-	if duration > minDuration {
-		return duration
-	}
-
-	return duration * time.Millisecond
-}
diff --git a/core/conf/time_test.go b/core/conf/time_test.go
deleted file mode 100644
index 130e0748..00000000
--- a/core/conf/time_test.go
+++ /dev/null
@@ -1,14 +0,0 @@
-package conf
-
-import (
-	"testing"
-	"time"
-
-	"github.com/stretchr/testify/assert"
-)
-
-func TestCheckedDuration(t *testing.T) {
-	assert.Equal(t, time.Second, CheckedDuration(1000))
-	assert.Equal(t, 2*time.Second, CheckedDuration(2000))
-	assert.Equal(t, 2*time.Second, CheckedDuration(time.Second*2))
-}