Realtek re(4) driver

[Gary Jennejohn]

On Wed, 11 Apr 2018 17:19:18 +0200
Alex Dupre <ale at FreeBSD.org> wrote:

> Gary Jennejohn wrote:
> > Reading the bugzilla shows that this is a comples problem with no
> > obvious error source.
> > 
> > One poster notes that he could transfer 300+GB of data error-free
> > using rsync, but with NFS he encountered problesm after a few GB. 
> > To me this is an indictment of the NFS implementation used and
> > not of the re driver itself.  
> I agree that is a complex problem with a non obvious solution, I have
> also used many re cards successfully and others not, but surely it's not
> a NFS issue. I can tell you more, I've used successfully a re card for
> years, and started seeing issues with the same card after upgrading my
> upstream connection to gigabit. The only thing that link all bug reports
> (and there are tons) is the use of re card sustaining gigabit (duplex)
> transfers. And I couldn't find similar reports for other chipsets that
> might lead to think it's a generic FreeBSD issue. Everything is
> possible, but the main suspect is the re driver.
> 

One thing which did seem common was checksum offloading.  My cards
don't seem to support that.

My Linux NFS server is serving clients with 1Gbps links - never
seen a problem.  But the MTU is limited to 1500.

The re in my FBSD box uses a MTU of 4808.  I've transferred lots
of data with a Linux device and a Windows machine also using that
setting and never saw a problem.  Maybe I'm just lucky.

The Realtech Linux driver could be a place to start looking for useful
changes.

-- 
Gary Jennejohn