diff --git a/boot.php b/boot.php
index d82669f23..44fbcda73 100644
--- a/boot.php
+++ b/boot.php
@@ -1046,11 +1046,21 @@ class App {
 	function save_timestamp($stamp, $value) {
 		$duration = (float)(microtime(true)-$stamp);
 
+		if (!isset($this->performance[$value])) {
+			// Prevent ugly E_NOTICE
+			$this->performance[$value] = 0;
+		}
+
 		$this->performance[$value] += (float)$duration;
 		$this->performance["marktime"] += (float)$duration;
 
 		$callstack = $this->callstack();
 
+		if (!isset($this->callstack[$value][$callstack])) {
+			// Prevent ugly E_NOTICE
+			$this->callstack[$value][$callstack] = 0;
+		}
+
 		$this->callstack[$value][$callstack] += (float)$duration;
 
 	}