disabling NIC features with ifconfig

C

chrcol

Ok I am currently diagnosing poor network performance on a remote server, I have one server performing very well and another badly on the same network. I have been trying to configure the poor one as like for like as the good one as possible and so far have had a little improvement.

Both servers are running 7.1 PRERELEASE code that is about 2-4 weeks old.

The difference I am looking at, at the moment is the good server is using a MSK card that has no hardware features like checksum offloading, no TSO but does have hardware VLAN.

The bad server is using a NFE card which currently has RXCSUM,TXCSUM,VLAN_MTU,TSO4 enabled, its also sharing a irq with a usb port. I then enabled polling which seemed to also help a bit. The usb port is idle tho.

What I want to do is disable RXCSUM and TXCSUM and the TSO4. I dont have console access. So would the following command work and the server stays online?

ifconfig nfe0 -txcsum -rxcsum -tso4

Also if this gives no benefit the machine has a BGE nic which I am considering to try using although will be a pain to swap it round as need datacentre staff to coordinate.

Thanks
 
Bad performance is usually due to duplex settings. Make sure the switch and the NIC is set to full duplex. Do not use auto/auto for duplex/speed settings.
 
ifconfig nfe0 -txcsum -rxcsum
I think this will slow down network. Really, better check your duplex settings, also check for errors with
netstat -wI 1 nfe0
 
Hi guys, it is using auto duplex but its auto negotiated at full duplex to match the switch, last time I tried to manual negitiate it the server disconnected of the internet and I had to reboot it. :(

No errors in netstat.

Reason I want to remove checksum is that the nvidia cards dont have a good reputation and I am reading so many scenarios where people disable checksum offloading to fix issues albeit on windows machines so it is something I wish to try to rule that out as the problem. I will try on monday and report back to you guys if any improvement or not.
 
SirDice said:
Bad performance is usually due to duplex settings. Make sure the switch and the NIC is set to full duplex. Do not use auto/auto for duplex/speed settings.
Click to expand...

Auto-negotiation is required for gigabit and faster connections. The only time one should not use auto-neg is on hubs, old 10/100 switches, or when locking in half-duplex operation.
 
ok rxcsum and txcsum disabled now with no downtime, will run it like this for a while and watch performance, thanks.
 
phoenix_rizzen said:
The only time one should not use auto-neg is on hubs, old 10/100 switches, or when locking in half-duplex operation.
Click to expand...
In theory, yes. In practice (about 10 years being a network admin) I know most performance problems are solved by fixating the speed/duplex settings. Auto-negotiation seems to fail on implementation differences between different brands of equipment (nic brand vs. switch brand). I've seen many times where the auto/auto resulted in 100/half instead of 100/full. Even on brand spanking new Cisco 6500s.
 
I can confirm disabling the hardware checksum has given a noticeable boost in performance, still not at the same level as the other server but a boost nevertherless.
 
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