src/java.base/share/classes/java/lang/Runtime.java

@@ -27,10 +27,11 @@
 
 import java.io.*;
 import java.util.StringTokenizer;
 import sun.reflect.CallerSensitive;
 import sun.reflect.Reflection;
+import jdk.internal.HotSpotIntrinsicCandidate;
 
 /**
  * Every Java application has a single instance of class
  * {@code Runtime} that allows the application to interface with
  * the environment in which the application is running. The current

@@ -873,10 +874,20 @@
         }
         ClassLoader.loadLibrary(fromClass, libname, false);
     }
 
     /**
+     * Method signifying that the caller is momentarily unable to
+     * progress until the occurrence of one or more actions of one or
+     * more other activities.  When invoked within each iteration, this
+     * method typically improves performance of spin wait loop
+     * constructions.
+     */
+    @HotSpotIntrinsicCandidate
+    public static void onSpinWait() {};
+
+    /**
      * Creates a localized version of an input stream. This method takes
      * an {@code InputStream} and returns an {@code InputStream}
      * equivalent to the argument in all respects except that it is
      * localized: as characters in the local character set are read from
      * the stream, they are automatically converted from the local