20% packet loss with re0 in gigE mode vs. 0% in 100BT
sean at mcneil.com
Mon Oct 11 13:09:08 PDT 2004
On Mon, 2004-10-11 at 12:31, Robert Watson wrote:
> On Mon, 11 Oct 2004, Sean McNeil wrote:
> > > Assuming you're not filling the send buffer, it would definitely suggest a
> > > driver, configuration, or hardware bug. There have recently been a number
> > > of changes to the if_re driver to fix support for jumbo frames, etc. It
> > > would be interesting to know whether backing out to earlier revisions of
> > > the if_re driver affect the problem you're seeing. In particular,
> > > ifre.c:1.35 was the jumbo frame change, so 1.34 would be interesting, and
> > > 1.31 is before some other related changes. Likewise, you could try
> > > backing out to before locking was introduced by setting debug.mpsafenet=0
> > > in loader.conf and then backing out to if_re.c:1.29. I might be generally
> > > useful to try setting debug.mpsafenet=0 with the current driver to
> > > eliminate that as a possible concern.
> > These are good suggestions as well, but I have heard from another user
> > that has seen this kind of thing over all of these versions. It is less
> > likely then that the jumbo or locking changes caused the issue.
> Have you tried 4.x to see if the same problem occurs there?
> Have you tried the normal juggling of ACPI, APIC, and other configuration
> variables? It sounds like things work fine at minimal bandwidth rates, so
> that probably rules out interrupt problems and the like, but I figured it
> was worth asking.
> I assume you've probably looked at substituting the switch, forcing
> auto-negotiation to 1gb, etc?
Again, I have failed to provide information that was sent in previous
emails under a different topic. I haven't tried 4.x, no, but I have
tried with various configurations:
Everything I have tested works just fine. It is only when the re0 under
FreeBSD is using PHY gigE that I have any packet loss. There is a small
chance that there is bursting that is causing the loss but I doubt it as
the output rate is 15Mbps. This is a pretty low rate and not very
likely to cause serious bursting.
I now have a source stream and a saved stream from a receiver. I will
attempt to examine the differences in them to see if it is just a matter
of some packets being dropped or if it is more nefarious.
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