e100 latency, cpu cycle saver and e1000...

[Paul Rolland]

Hello,

A few days ago, there was a thread about e100 latency related to
CPU Cycle Saver...

Suggestion was to disabled it to return back to some "standard"
latency.

At the moment, I'm experiencing some strange behavior, not with
an e100 but with an e1000 on a 2.4.20 kernel...

Here are some traces, using Corey Minyard test application :

[root@IP3 tmp]# ./test IP1 32000 10000 370
Average: 201us, Max: 631us, Min: 200us
[root@IP3 tmp]# ./test IP2 32000 10000 370
Average: 422us, Max: 47581us, Min: 209us

All three machines are using 2.4.20 and e1000 drivers, they are
the same hardware.

But, definitely, IP2 is exhibiting much higher max latency...

Increasing the packet size up to 1200 bytes doesn't change the 
global behavior : IP2 is always much "latent" than IP1...

The problem is that it seems there is no CPU Cycle Saver on e1000
NIC. Is there some equivalent ? Could someone give a guess on
what's going on ?

Regards,
Paul