NFS on 10G interface terribly slow

[Gerrit Kühn]

On Fri, 26 Jun 2015 20:42:08 -0400 (EDT) Rick Macklem
<rmacklem at uoguelph.ca> wrote about Re: NFS on 10G interface terribly slow:

RM> Btw, can you tell us what Intel chip(s) you're using?

I have

ix0 at pci0:5:0:0: class=0x020000 card=0x00028086 chip=0x15288086 rev=0x01
hdr=0x00 vendor     = 'Intel Corporation'
    device     = 'Ethernet Controller 10-Gigabit X540-AT2'
    class      = network
    subclass   = ethernet

RM> For example, from the "ix" driver:
RM> #define IXGBE_82598_SCATTER		100
RM> #define IXGBE_82599_SCATTER		32

Hm, I cannot find out into which chipset number this translates for my
device...

RM> Btw, it appears that the driver in head/current now sets
RM> if_hw_tsomaxsegcount, but the driver in stable/10 does not. This means
RM> that the 82599 chip will end up doing the m_defrag() calls for 10.x.

So the next step could even be updating to -current...
OTOH, I get the same (bad) resulsts, no matter if TSO is enabled or
disabled on the interface.


cu
  Gerrit