select() with doing multiple accept()s. Idea is to
reduce the cost of each select(). How to avoid blocking on accept()---must
be using non-blocking version.
Results (Fig 6-8) show significant dropoff in throughput by using select()
and /dev/poll as the request rate increases.
Using multi-accept amortizes the costs of select() and gives it comparable,
if not better, throughput performance than other approaches. Helps to make
the interest set of select() more dense.
Needing to combine RT signals with another mechanism is ugly and error-prone.