Using the evcnt infrastructure in NetBSD, any experience?

[buhrow%lothlorien.nfbcal.org@localhost (Brian Buhrow)]

        hello. We're using NetBSD in a number of routing applications and
we're interested in improving the instrumentation available on network
interfaces.  In particular, we'd like to know things like numbers of bad
frames, crc errors, buffer failures and the like.  It looks like some of
that work has been done with the evcnt infrastructure in the kernel, and it
even looks like many of the network drivers have been enhanced to provide
much of that data to the underlying infrastructure.  The only problem is
that it looks like most of that additional code is ifdefed out with various
driver specific options.  
        Right now, we're using NetBSD-3 in our most dejmanding application,
but we would be willing to consider moving forward if we feel confident the
newer stuff is as stable as netBSD-3 has been.
        So, my question is, has anyone turned on those extra event counting
options in any of the network drivers, and, if so, did you find that things
were just as stable as they were without those options enabled?  I can turn
them on, but I'd like to know if someone has gone before me.

-thanks
-'Brian