Problems with jumbo frames on nfe

[Pyun YongHyeon]

On Tue, May 19, 2009 at 11:31:02AM +0200, Pascal Braun wrote:
> Hi,
> 
> I'm currently testing jumbo frames on a Sunfire 4540 running with 
> FreeBSD 8-Current (build on April 8th). While using the nfe driver I'm 
> having some unexpected problems if i try to bring up the interface with 
> MTU sizes greater than 1970 bytes.
> 
> The error message (in dmesg) is:
> nfe2: initialization failed: no memory for rx buffers
> 

It means you've run out of jumbo clusters. Check the output of
"netstat -m" and see how many jumbo cluster requests were denied.

> I tried to deactivate checksum offloading with -rxcsum -txcsum, but that 
> didn't help either.
> 

Yeah, that has nothing to do with jumbo frame support.

> If I change the mtu size on-the-fly without bringing the interface down 
> first, no error is logged. But the interface just isn't working.
> 

nfe(4) is smart enough not to allocate jumbo clusters if interface
is DOWN.

> Does anyone have any ideas how to get jumbo frames working?
> 

How about increasing 9K jumbo clusters(kern.ipc.nmbjumbo9) with
sysctl(8)?

> Regards
> Pascal