Thank you for the comments, Jonathan.

Taking into consideration what you've said, one is left to ask,
what use is an MSIZE of 256 ?

Is it because use of NetBSD is mainly geared towards uses where
the average packet is 200 bytes or so in size ?

If so, what use is that ?
FTP server ?
NFS server ?
Web server ?
Email server ?
ping server ?
SMB server ?
student server for ssh access (no NFS, etc) ?

Another question is, should someone be expected to recompile a
kernel in order to tune/adjust this to best meet their needs or
should the system just work and self-tune out of the box ?

It would be interesting to count in m_freem how many mbufs are
cascaded vs single entities or even try and discover what the
distribution of mbuf chain sizes is.  Or is there a better place
to measure this, such as IF_ENQUEUE ?

Darren