You have multiple options here. For example, you could just add a cyclic callback event like this:

my $teatime = $mw->repeat(50, \&updateGraphs);

...

sub updateGraphs {
    ...
    return;
}
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Instead of calling MainLoop, you could look into using something like DoOneEvent(), but i couldn't find it in my own codebase, so i can't be sure it works.