diff --git a/tools/libxl/libxl_event.c b/tools/libxl/libxl_event.c
index b50d4e5074..3e76fa5af5 100644
--- a/tools/libxl/libxl_event.c
+++ b/tools/libxl/libxl_event.c
@@ -1417,6 +1417,7 @@ static void afterpoll_internal(libxl__egc *egc, libxl__poller *poller,
     }
 
     if (afterpoll_check_fd(poller,fds,nfds, poller->wakeup_pipe[0],POLLIN)) {
+        poller->pipe_nonempty = 0;
         int e = libxl__self_pipe_eatall(poller->wakeup_pipe[0]);
         if (e) LIBXL__EVENT_DISASTER(gc, "read wakeup", e, 0);
     }
@@ -1809,6 +1810,8 @@ void libxl__poller_put(libxl_ctx *ctx, libxl__poller *p)
 
 void libxl__poller_wakeup(libxl__gc *gc, libxl__poller *p)
 {
+    if (p->pipe_nonempty) return;
+    p->pipe_nonempty = 1;
     int e = libxl__self_pipe_wakeup(p->wakeup_pipe[1]);
     if (e) LIBXL__EVENT_DISASTER(gc, "cannot poke watch pipe", e, 0);
 }
diff --git a/tools/libxl/libxl_internal.h b/tools/libxl/libxl_internal.h
index f2ff5e6c2d..2555aa4575 100644
--- a/tools/libxl/libxl_internal.h
+++ b/tools/libxl/libxl_internal.h
@@ -625,6 +625,7 @@ struct libxl__poller {
     int (*fd_rindices)[3]; /* see libxl_event.c:beforepoll_internal */
 
     int wakeup_pipe[2]; /* 0 means no fd allocated */
+    bool pipe_nonempty;
 
     /*
      * We also use the poller to record whether any fds have been