Jakub Kicinski [off-list ref]

Sent: Wednesday, April 21, 2021 2:34 AM

[...]

quoted

We test 2.5G Ethernet on some embedded platform.
And we find 64 is not large enough, and the performance
couldn't reach 2.5 G bits/s.

Did you manage to identify what the cause is?

NAPI will keep calling your driver if the budget was exhausted, the
only difference between 64 and 256 should be the setup cost of the
driver's internal loop. And perhaps more frequent GRO flush - what's
the CONFIG_HZ set to?

I am not sure. It is more than one year ago.
The CONFIG_HZ may be 250.

First, the CPU of that platform is slower than a x86 platform.
Then, the rx data comes very fast, because of the 2.5G Ethernet.
We find the budget is always exhausted, when the traffic is busy.

Best Regards,
Hayes