neigh_periodic_timer (neigh_table_init_no_netlink) excessive timer wakeups

[Andreas Mohr]

Hi,

On Wed, Mar 26, 2008 at 10:09:12AM +0100, Andreas Mohr wrote:
> I'll do a HZ=100 test run now and possibly further code investigation
> as time permits, however one thing is obvious: compared to other
> timer system activity this one is very visible and should be tackled
> one way or another.

OK, with HZ=100 I now always get _exactly_ 50,0 neigh table wakeups:

  38,6% ( 50,2)              lisa : neigh_add_timer (neigh_timer_handler)
  38,5% ( 50,0)     <kernel core> : neigh_table_init_no_netlink (neigh_periodic_ti

(and I conveniently managed to catch the rare lisa activity here as
well)

Not sure what this different number should tell me, though
(after all it's not directly proportional to the 100 <-> 300 change).
The only way for me to gain sufficient insight about this would be to dive
into the inner handling and interval calculation, tree size etc. again.

Andreas Mohr