erts: Improve driver_SUITE:smp_select

to better detect an actual missing ready_input event
on slow machines (valgrind)
and without wasting time with long sleep on fast machines.

1 files changed, 16 insertions, 1 deletions

diff --git a/erts/emulator/test/driver_SUITE.erl b/erts/emulator/test/driver_SUITE.erl
index 6f5d639d04..bd62708aa7 100644
--- a/erts/emulator/test/driver_SUITE.erl
+++ b/erts/emulator/test/driver_SUITE.erl
@@ -1754,7 +1754,7 @@ smp_select0(Config) ->
     ProcFun = fun()-> io:format("Worker ~p starting\n",[self()]),	
                       Port = open_port({spawn, DrvName}, []),
                       smp_select_loop(Port, 100000),
-                      sleep(1000), % wait for driver to handle pending events
+                      smp_select_done(Port),
                       true = erlang:port_close(Port),
                       Master ! {ok,self()},
                       io:format("Worker ~p finished\n",[self()])
@@ -1784,6 +1784,21 @@ smp_select_loop(Port, N) ->
               smp_select_loop(Port, N-1)
     end.
 
+smp_select_done(Port) ->
+    case erlang:port_control(Port, ?CHKIO_SMP_SELECT, "done") of
+        "wait" ->
+            receive
+                {Port, done} ->
+                    ok
+            after 10*1000 ->
+                    %% Seems we have a lost ready_input event.
+                    %% Go ahead anyway, port will crash VM when closed.
+                    ok
+            end;
+
+        "ok" -> ok
+    end.
+
 smp_select_wait([], _) ->
     ok;
 smp_select_wait(Pids, TimeoutMsg) ->