The old code was doing a floating point divide for each rte_dequeue()
which is very expensive. Change to using fixed point scaled inverse
multiply. To maintain equivalent precision, scaled math is used.
The application ABI is the same.
This improved performance from 5Gbit/sec to 10 Gbit/sec when configured
for 10 Gbit/sec rate.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
03d00293ca