No lo he probado…

$start = microtime();
$status1 = SHOW GLOBAL STATUS LIKE Questions;
for ( 1 .. 100 ) {
$num_running += SELECT COUNT(*) FROM SHOW PROCESSLIST WHERE Command = Query;
}
$time = microtime() – $start;
return 0 unless $time;
$status2 = SHOW GLOBAL STATUS LIKE Questions;
$qps = ($status2 – $status1) / $time;
return 0 unless $qps;
return ($num_running / 100) / $qps;

Para más información sobre el script podéis visitar la web del Xapbr