imx6q: poor FEC Gigabit implementation

Hello,

I did some Gigabit performance measurements with the i.MX6Q Sabrelite board. I measure an UDP throughput of 470 Mb/s to an external host, which is already very close to the theoretical limit listed in the Chip Errata ERR004512 for the i.MX 6Dual/6Quad, Rev. C, 2/2012.

At a closer look to the driver I realized that there is no support for

- NAPI
- IP checksum offloading
- Jumbo frames

According to the manual, these features are support by the ENET via enhanced buffer descriptors. Even if they will not increase the performance due to the mentioned system limitation, they should reduce the interrupt and CPU load significantly. I did some quick tests with IP checksum offloading and Jumbo frames but without success. Are there any known issues? Is anybody already working on an enhanced FEC Gigabit ethernet driver?

TIA.

Wolfgang.