diff --git a/tokio/src/io/driver/registration.rs b/tokio/src/io/driver/registration.rs
index 7350be6345d..181d2349f86 100644
--- a/tokio/src/io/driver/registration.rs
+++ b/tokio/src/io/driver/registration.rs
@@ -247,12 +247,14 @@ cfg_io_readiness! {
         }
 
         pub(crate) async fn async_io<R>(&self, interest: Interest, mut f: impl FnMut() -> io::Result<R>) -> io::Result<R> {
+            println!("Tokio Registration::async_io() {}:{}", file!(), line!());
             loop {
                 let event = self.readiness(interest).await?;
-
+                println!("Tokio Registration::async_io() self.readiness({:?}) = {:?} returned @ {}:{}", interest, event, file!(), line!());
                 match f() {
                     Err(ref e) if e.kind() == io::ErrorKind::WouldBlock => {
                         self.clear_readiness(event);
+                        println!("Tokio Registration::async_io() self.clear_readiness() {}:{}", file!(), line!());
                     }
                     x => return x,
                 }
diff --git a/tokio/src/net/tcp/listener.rs b/tokio/src/net/tcp/listener.rs
index 273b7db0337..c51390cc618 100644
--- a/tokio/src/net/tcp/listener.rs
+++ b/tokio/src/net/tcp/listener.rs
@@ -158,13 +158,15 @@ impl TcpListener {
     /// }
     /// ```
     pub async fn accept(&self) -> io::Result<(TcpStream, SocketAddr)> {
+        println!("Tokio TcpListener::accept() {}:{}", file!(), line!());
         let (mio, addr) = self
             .io
             .registration()
             .async_io(Interest::READABLE, || self.io.accept())
             .await?;
-
+        println!("Tokio TcpListener::accept() self.io.registration().async_io().await {}:{}", file!(), line!());
         let stream = TcpStream::new(mio)?;
+        println!("Tokio TcpListener::accept() TcpStream::new() {}:{}", file!(), line!());
         Ok((stream, addr))
     }