fix(http1): fix consuming extra CPU from previous change (#3977)

Revert "fix(http1): fix rare missed write wakeup on connections (#3952)"

This reverts commit 2377b89.

Author: seanmonstar

Cargo.toml

@@ -239,11 +239,6 @@ name = "integration"
 path = "tests/integration.rs"
 required-features = ["full"]
 
-[[test]]
-name = "ready_stream"
-path = "tests/ready_stream.rs"
-required-features = ["full"]
-
 [[test]]
 name = "server"
 path = "tests/server.rs"

src/proto/h1/dispatch.rs

@@ -171,13 +171,8 @@ where
         for _ in 0..16 {
             let _ = self.poll_read(cx)?;
             let _ = self.poll_write(cx)?;
-            let conn_ready = self.poll_flush(cx)?.is_ready();
+            let _ = self.poll_flush(cx)?;
 
-            // If we can write more body and the connection is ready, we should
-            // write again. If we return `Ready(Ok(())` here, we will yield
-            // without a guaranteed wakeup from the write side of the connection.
-            // This would lead to a deadlock if we also don't expect reads.
-            let wants_write_again = self.can_write_again() && conn_ready;
             // This could happen if reading paused before blocking on IO,
             // such as getting to the end of a framed message, but then
             // writing/flushing set the state back to Init. In that case,
@@ -186,10 +181,7 @@ where
             //
             // Using this instead of task::current() and notify() inside
             // the Conn is noticeably faster in pipelined benchmarks.
-            let wants_read_again = self.conn.wants_read_again();
-            // If we cannot write or read again, we yield and rely on the
-            // wakeup from the connection futures.
-            if !(wants_write_again || wants_read_again) {
+            if !self.conn.wants_read_again() {
                 //break;
                 return Poll::Ready(Ok(()));
             }
@@ -441,11 +433,6 @@ where
         self.conn.close_write();
     }
 
-    /// If there is pending data in body_rx, we can make progress writing if the connection is ready.
-    fn can_write_again(&mut self) -> bool {
-        self.body_rx.is_some()
-    }
-
     fn is_done(&self) -> bool {
         if self.is_closing {
             return true;