diff --git a/src/unix/ev_loop.ml b/src/unix/ev_loop.ml
index 6310ac9b..d8e85263 100644
--- a/src/unix/ev_loop.ml
+++ b/src/unix/ev_loop.ml
@@ -153,6 +153,7 @@ module Ev_loop = struct
         (** Is the ev loop thread currently waiting? *)
     pipe_read: Unix.file_descr;  (** Main thread only *)
     pipe_write: Unix.file_descr;  (** Wakeup main thread *)
+    b4: bytes;  (** small buffer *)
   }
 
   let create () : t =
@@ -166,6 +167,7 @@ module Ev_loop = struct
       actions = Action_queue.create ();
       pipe_read;
       pipe_write;
+      b4 = Bytes.create 4;
     }
 
   (** Perform the action from within the ev loop thread *)
@@ -188,14 +190,14 @@ module Ev_loop = struct
 
   (** Empty the pipe *)
   let drain_pipe_ (self : t) : unit =
-    let b = Bytes.create 1 in
     try
       let continue = ref true in
       while !continue do
-        let n = Unix.read self.pipe_read b 0 1 in
-        if n = 0 then continue := false
+        match Unix.read self.pipe_read self.b4 0 (Bytes.length self.b4) with
+        | n -> if n = 0 then continue := false
+        | exception Unix.Unix_error (Unix.EAGAIN, _, _) -> ()
       done
-    with Unix.Unix_error ((Unix.EAGAIN | Unix.EWOULDBLOCK), _, _) -> ()
+    with Unix.Unix_error (Unix.EWOULDBLOCK, _, _) -> ()
 
   let run_step_ (self : t) : unit =
     perform_pending_actions self;
@@ -207,11 +209,18 @@ module Ev_loop = struct
     let reads, writes = IO_tbl.prepare_select self.io_tbl in
     A.set self.in_blocking_section true;
     let reads, writes, _ =
+      Tracing_.message
+        (Printf.sprintf "select: %d read (+selfpipe), %d writes"
+           (List.length reads) (List.length writes));
       let@ _sp = Tracing_.with_span "moonpool-unix.evloop.select" in
       Unix.select (self.pipe_read :: reads) writes [] delay
     in
     A.set self.in_blocking_section false;
 
+    Tracing_.message
+      (Printf.sprintf "select: %d read ready, %d writes ready"
+         (List.length reads) (List.length writes));
+
     drain_pipe_ self;
     IO_tbl.handle_ready ~ignore_read:self.pipe_read self.io_tbl reads writes;