here it is...
Code:
alias lagcheck {
  if ($server) {
    .!ctcp $me LAG $ticks 
  } 
}
ctcp *:LAG:*:if ($cid == $activecid) { redraw_value $calc(($ticks - $2) / 1000) } | halt
on *:connect:{
  lagcheck
  .timerlag 0 10 lagcheck
}
on *:disconnect:{
  .timerlag off
  init_lag_face
}

But I'm afraid it will also reset idle timer... crazy