8307425: Socket input stream read burns CPU cycles with back-to-back …

…poll(0) calls

Reviewed-by: alanb

src/java.base/share/classes/sun/nio/ch/DatagramChannelImpl.java

@@ -78,6 +78,9 @@
 import sun.net.ext.ExtendedSocketOptions;
 import sun.net.util.IPAddressUtil;
 
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
+import static java.util.concurrent.TimeUnit.NANOSECONDS;
+
 /**
  * An implementation of DatagramChannels.
  */
@@ -497,7 +500,12 @@ public void park(int event, long nanos) throws IOException {
             if (nanos == 0) {
                 millis = -1;
             } else {
-                millis = TimeUnit.NANOSECONDS.toMillis(nanos);
+                millis = NANOSECONDS.toMillis(nanos);
+                if (nanos > MILLISECONDS.toNanos(millis)) {
+                    // Round up any excess nanos to the nearest millisecond to
+                    // avoid parking for less than requested.
+                    millis++;
+                }
             }
             Net.poll(getFD(), event, millis);
         }

src/java.base/share/classes/sun/nio/ch/NioSocketImpl.java

@@ -182,6 +182,11 @@ private void park(FileDescriptor fd, int event, long nanos) throws IOException {
                 millis = -1;
             } else {
                 millis = NANOSECONDS.toMillis(nanos);
+                if (nanos > MILLISECONDS.toNanos(millis)) {
+                    // Round up any excess nanos to the nearest millisecond to
+                    // avoid parking for less than requested.
+                    millis++;
+                }
             }
             Net.poll(fd, event, millis);
         }

src/java.base/share/classes/sun/nio/ch/SelChImpl.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2022, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2023, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,6 +28,8 @@
 import java.nio.channels.Channel;
 import java.io.FileDescriptor;
 import java.io.IOException;
+
+import static java.util.concurrent.TimeUnit.MILLISECONDS;
 import static java.util.concurrent.TimeUnit.NANOSECONDS;
 
 /**
@@ -90,6 +92,11 @@ default void park(int event, long nanos) throws IOException {
                 millis = -1;
             } else {
                 millis = NANOSECONDS.toMillis(nanos);
+                if (nanos > MILLISECONDS.toNanos(millis)) {
+                    // Round up any excess nanos to the nearest millisecond to
+                    // avoid parking for less than requested.
+                    millis++;
+                }
             }
             Net.poll(getFD(), event, millis);
         }