Realtek re(4) driver

[Dieter BSD]

Built a kernel with Realtek's Ethernet driver.
The 8111E & 8111F work, although initial testing using nc(1) is being
a bit strange.

1st testing window:
  re0 I tried the same copy a 28 GB file using nc(1) and udp.
  The 1st & 3rd try gave the correct number of bytes, but
  the 2nd try was short.
  The other 2 ports (re1 re2) worked less well.

2nd testing window:
  re0 (8111F on Syba 2 port PCIe card [1])
    6 times 28 GB file using nc and udp 3 "plain" and 3 with -T reliability
    1 "plain" copy worked correctly, the other 5 were short
  re1 (2nd 8111F port on PCIe card)
    all 5 attempts were short, 3 of 5 were very short:
    28132560000    goal
    27982918784 big_file_copied_via_udp_re1_0
    27981835392 big_file_copied_via_udp_re1_1
         587776 big_file_copied_via_udp_re1_2
         608256 big_file_copied_via_udp_re1_3
         606208 big_file_copied_via_udp_re1_Trel_0
  re2 (8111E on UD5 mainboard)
    all 6 attempts were short
       32452608 big_file_copied_via_udp_re2rt_0
        3932160 big_file_copied_via_udp_re2rt_1
      399364096 big_file_copied_via_udp_re2_Trel_0
        5963776 big_file_copied_via_udp_re2_Trel_1
        4159488 big_file_copied_via_udp_re2_Trel_2
        4827136 big_file_copied_via_udp_re2_2
    28132560000    goal

One burst and then it fails:
            input            re2           output
   packets  errs idrops      bytes    packets  errs      bytes colls
         0     0     0          0          0     0          0     0
         0     0     0          0          0     0          0     0
         0     0     0          0          0     0          0     0
      3840     0     0    4078080          0     0          0     0
         0     0     0          0          0     0          0     0
         0     0     0          0          0     0          0     0
         0     0     0          0          0     0          0     0
         0     0     0          0          0     0          0     0
         0     0     0          0          0     0          0     0
         0     0     0          0          0     0          0     0

For real world use, so far the Realtek driver is working at least as well
as the stock FreeBSD 10.3 driver, probably better.  But it does lose data
with real world applications, (2 separate incidents so far) so it needs
improvement.

Some of the test results with nc(1) are kinda screwy.  Maybe nc is the
wrong tool, maybe I'm using it wrong, I don't know.

Has anyone tried similar testing?
Suggestions of knobs to turn, or other things to try?

I need to receive data via UDP without dropping packets.  Closed source sucks,
but I'm stuck with it, and thus with UDP.

[1] http://www.sybausa.com/index.php?route=product/product&manufacturer_id=11&product_id=130&page=25
$21.22