Broadcom BCM5788 jumbo frames? (FBSD 5.2.1)

[Mike Hunter]

Hi,

I have a Broadcom BCM5788 card that I'd like to use with jumboframes, but
it seems that the card (or the driver) only allows a max of 1500 MTU.

ifconfig bge0 mtu 9000
ifconfig: ioctl (set mtu): Invalid argument

1500 and less works.

I had this problem with my BCM5707M, and lo and behold if you look in
if_bge.c it says it can't do it, but I looked and I can't find a similar
comment for the BCM5788.

Any thoughts?  The system in question is 5.2.1-RELEASE-p3.  The bge card
is builtin to the motherboard (shuttle sb75g2 on 64 bit pci.)

While I have everybody's attention, what's a reasonable goal for
throughput between two of these cards?  I broke through the 33mhz pci
barrier and am now getting iperf results of:

[  6]  0.0-10.0 sec   535 MBytes   449 Mbits/sec

( Obviously, without jumbo frames.)

I've increased the tcp send and recv space....Any other suggestions?

Thanks,

Mike