This line waits forever for input:

while(@bits = $selectFD->can_read)
[download]

and then this line pauses for a tenth of second for no apparent reason:

select(undef, undef, undef, 0.1);
[download]

What you probably want to do is:

@bits = $selectFD->can_read(30);
if (@bits == 0) {
  # we timed out
} else {
  for (@bits) {
    blah blah blah
  }
}
[download]