How to get NFS reads >1024 bytes?

[Dave Martindale]

It seems that the A/UX NFS client code never does reads of more than
1024 bytes in one request to the server.  Is there any way of getting
around this limitation?

Our other NFS machines show much better NFS performance when they
read large blocks (e.g. 8192 bytes).  However, I cannot get the
Mac to do the same.  I've tried using "rsize=8192" when doing the mount,
and using "dd" to make sure that the user code was using a large buffer,
to no avail.

Is there a tunable kernel parameter that controls this? (I looked and
couldn't find one).  Or is the problem that the Ethernet card can't
handle more than one packet at a time, and forces all requests to be
less than or equal to 1024 bytes to ensure that just one packet will
come back?  In that case, can I get at least a full Ethernet packet
(1536 bytes)?