or how about this...?

tokio/src/runtime/scheduler/multi_thread/idle.rs

@@ -150,6 +150,12 @@ impl Idle {
         lock.idle.sleepers.contains(&worker_id)
     }
 
+    /// Returns `true` if all other workers are currently parked.
+    pub(super) fn all_parked(&self) -> bool {
+        let state = State(self.state.fetch_add(0, SeqCst));
+        state.num_unparked() <= 1
+    }
+
     fn notify_should_wakeup(&self) -> bool {
         let state = State(self.state.fetch_add(0, SeqCst));
         state.num_searching() == 0 && state.num_unparked() < self.num_workers

tokio/src/runtime/scheduler/multi_thread/worker.rs

@@ -1352,8 +1352,6 @@ impl Handle {
         let should_notify = if is_yield || !core.lifo_enabled {
             core.run_queue
                 .push_back_or_overflow(task, self, &mut core.stats);
-            // Always notify another parked worker when pushing a yielded task
-            // to the main run queue if we are not currently parked.
             true
         } else {
             // Push to the LIFO slot
@@ -1362,19 +1360,9 @@ impl Handle {
                 // to be pushed to the back of the run queue.
                 core.run_queue
                     .push_back_or_overflow(prev, self, &mut core.stats);
-                // We have pushed the previous LIFO task to the back of the run
-                // queue, so we should attempt to notify another worker if we
-                // are not currently parked.
                 true
             } else {
-                // If the scheduled task was pushed to the LIFO slot and there
+                self.shared.idle.all_parked()
-                // is no other task previously in the slot, skip notifying
-                // another worker, so that we can preferentially poll the LIFO
-                // task next. It can still be stolen if another worker is
-                // searching. This reduces cross thread notifications, and
-                // reduces the chance of the LIFO task moving across threads if
-                // the next poll is short.
-                false
             }
         };