I am running Oracle Linux 7.3. I have a small tk application which mimics
the old xmessage program. It simply draws a window with three labels, but
the drawing is very, very slow. First the outside frame will be drawn,
then the labels, one after the other with several hundred milliseconds
delay between each.

I ran strace and saw that recvmsg was hanging a lot with EAGAIN errors.

Would anyone know what is causing this?

I originally was running a 'wish' which I built from source and thought
there were options missed in the build; I installed the current package,
tk.x86_64 1:8.5.13-6.el7 (plus the corresponding tcl package), but with
the same behaviour.

Regards,
Noel Hunt

I tracked the problem down to the fact that the application was
waiting for a 'Configure' event to set the final geometry. If I
remove the binding on '<Configure>' the window and its children
are immediately drawn.