Network Performace

Shawn Ramsey shawn at
Wed Jun 25 03:29:14 PDT 2003

> That's certainly a step in the right direction :)
> > But something is still very
> > wrong performance wise. It has helped, but I still can't push in/out
> > nearly 100Mb/sec. (100Mb in, 100Mb out I mean). A simple FTP transfer
> > locally through the routers gigabit interface causes our internet
> > performance to plummet. I've disabled all the onboard stuff that was
> > sharing IRQs with PCI cards, but I didn't figure that was an issue,
> > didn't make a difference either way. Would the fact the gigabit is on
> > same PCI bus have any bearing? I would expect to at least get 100BT
> > performance even so, but I don't have any experience with gigabit
> > ethernet...
> The only thing I can suggest is try different PCI slots, or Gigabit cards,
> or, worst case a different system. Having NIC's on separate PCI busses (as
> opposed to both on the same PCI bus) may help it [But that's probably
> to need a new board etc.]

Thats what I was going to try next, but i've noticed this :

gw# netstat -I xl0 -w 1
           input          (xl0)           output
  packets  errs      bytes    packets  errs      bytes colls
     7120    11    9118416       5566     0    2507132     0
     6754     6    8498898       5649     0    3009719     0
     7104     9    8856812       5802     0    3004529     0
     7737    19    9787501       6429     0    2994557     0
     7551    16    9670490       5948     0    2761794     0

I would guess such a large number of errors per second could be causing the
interrupt usuage? From what i've been able to find such input errors are
usually caused by a bad cable, or switch...

> You don't say what Gigabit nic's your using? - I've had a lot of varied
> results with different nic's, with surprisingly cheap 10/100/1000Mbit
> giving 'reasonable' performance - but get left standing for dust by other
> more expensive cards.

Its an Intel Fiber card, don't know the exact model offhand...

> The only other thing I can think of is, check the duplex/media options are
> all setup properly on the cards / switches etc. - or try forcing things to
> fdx etc.

Been there, done that, full duplex/autoselect makes no difference, but its
currently set for full/1000SX on both ends.

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