implications of SMP kernel on UP

[Colin Percival]

At 08:10 01/04/2004, Bjoern A. Zeeb wrote:
>what are the implications on running an SMP enabled kernel on a UP
>machine ?
>
>I first thought of things like:
>- performence (most likely not worth the discussion ?)

  At least in 5.2-RELEASE, there is a significant performance
delta; buildworld takes about 5% longer on an SMP kernel (and
the time spent in the kernel is 20% longer).
  I know some optimizations were done shortly after 5.2, so I
wouldn't be surprised if this situation has improved.

Colin Percival