diff --git a/runtime/src/main/kotlin/kotlin/system/Timing.kt b/runtime/src/main/kotlin/kotlin/system/Timing.kt
index 573f63a2e3f..9d205f3b621 100644
--- a/runtime/src/main/kotlin/kotlin/system/Timing.kt
+++ b/runtime/src/main/kotlin/kotlin/system/Timing.kt
@@ -6,19 +6,22 @@
 package kotlin.system
 
 /**
- * Gets current system time in milliseconds since epoch
+ * Gets current system time in milliseconds since certain moment in the past,
+ * only delta between two subsequent calls makes sense.
  */
 @SymbolName("Kotlin_system_getTimeMillis")
 public external fun getTimeMillis() : Long
 
 /**
- * Gets current system time in nanoseconds since epoch
+ * Gets current system time in nanoseconds since certain moment in the past,
+ * only delta between two subsequent calls makes sense.
  */
 @SymbolName("Kotlin_system_getTimeNanos")
 public external fun getTimeNanos() : Long
 
 /**
- * Gets current system time in microseconds since epoch
+ * Gets current system time in microseconds since certain moment in the past,
+ * only delta between two subsequent calls makes sense.
  */
 @SymbolName("Kotlin_system_getTimeMicros")
 public external fun getTimeMicros() : Long