Low network throughput on i.MX28

[Stefan Wahren]

Am 02.11.2016 um 09:14 schrieb Jörg Krause:
> On Sat, 2016-10-29 at 11:08 +0200, Stefan Wahren wrote:
>>> Jörg Krause <joerg.krause at embedded.rocks> hat am 29. Oktober 2016
>>> um 01:07
>>> geschrieben:
>>>
>>>
>>> You mentioned [1] an optimization in the Freescale vendor Linux
>>> kernel
>>> [2]. I would really like to see this optimization in the mainline
>>> kernel.
>>>
>>> Did you ever tried to port this code from Freescale to mainline?
>> Yes, i tried once but i was frustrated soon because of the lot of
>> required
>> changes and resulting issues.
> I got the PIO mode working for the mxs-mmc driver. For this I ported
> the PIO code from the vendor kernel and removed the usage of the DMA
> engine entirely.

Good job

>
> Testing network bandwidth with iperf, I get about ~10Mbit/sec with PIO
> mode compared to ~6.5Mbit/sec with DMA mode for UDP and about
> ~6.5Mbit/sec compared to ~4.5Mbit/sec with DMA mode for TCP.

And how about MMC / sd card performance?