RFC: How to fix the NFS/iSCSI vs TSO problem

[Marcelo Araujo]

Hello All,


2014-03-27 8:27 GMT+08:00 Rick Macklem <rmacklem at uoguelph.ca>:
>
> Well, bumping it from 32->35 is all it would take for NFS (can't comment
> w.r.t. iSCSI). ixgbe uses 100 for the 82598 chip and 32 for the 82599
> (just so others aren't confused by the above comment). I understand
> your point was w.r.t. using 100 without blowing the kernel stack, but
> since the testers have been using "ix" with the 82599 chip which is
> limited to 32 transmit segments...
>
> However, please increase any you know can be safely done from 32->35, rick
>
>
I have plenty of machines using Intel X540 that is based on 82599 chipset.
I have applied Rick's patch on ixgbe to check if the packet size is bigger
than 65535 or cluster is bigger than 32. So far till now, on FreeBSD
9.1-RELEASE this problem does not happens.

Unfortunately all my environment here is based on 9.1-RELEASE, with some
merges from 10-RELEASE such like: NFS and IXGBE.

Also I have applied the patch that Rick sent in another email with the
subject 'NFS patch to use pagesize mbuf clusters'. And we can see some
performance boost over 10Gbps Intel. However here at the company, we are
still doing benchmarks. If someone wants to have my benchmark result, I can
send it later.

I'm wondering, if this update on ixgbe from 32->35 could be applied also
for versions < 9.2. I'm thinking, that this problem arise only on 9-STABLE
and consequently on 9.2-RELEASE. And fortunately or not 9.1-RELEASE doesn't
share it.

Best Regards,
-- 
Marcelo Araujo
araujo at FreeBSD.org