Re: [PATCH 0/3] net: fec: updates to align IP header

[Eric Nelson <eric@nelint.com>]

On 09/24/2016 08:09 AM, Andy Duan wrote:
> From: Eric Nelson <eric@nelint.com> Sent: Saturday, September 24, 2016 10:42 PM
>> To: netdev@vger.kernel.org
>> Cc: linux@arm.linux.org.uk; andrew@lunn.ch; Andy Duan
>> <fugang.duan@nxp.com>; otavio@ossystems.com.br;
>> edumazet@google.com; troy.kisky@boundarydevices.com;
>> davem@davemloft.net; u.kleine-koenig@pengutronix.de; Eric Nelson
>> <eric@nelint.com>
>> Subject: [PATCH 0/3] net: fec: updates to align IP header
>>
>> This patch series is the outcome of investigation into very high numbers of
>> alignment faults on kernel 4.1.33 from the linux-fslc
>> tree:
>>     https://github.com/freescale/linux-fslc/tree/4.1-1.0.x-imx
>>
>> The first two patches remove support for the receive accelerator (RACC)
>> from the i.MX25 and i.MX27 SoCs which don't support the function.
>>
>> The third patch enables hardware alignment of the ethernet packet payload
>> (and especially the IP header) to prevent alignment faults in the IP stack.
>>
>> Testing on i.MX6UL on the 4.1.33 kernel showed that this patch removed on
>> the order of 70k alignment faults during a 100MiB transfer using wget.
>>
>> Testing on an i.MX6Q (SABRE Lite) board on net-next (4.8.0-rc7) showed a
>> much more modest improvement from 10's of faults, and it's not clear why
>> that's the case.
>>
>> Eric Nelson (3):
>>   net: fec: remove QUIRK_HAS_RACC from i.mx25
>>   net: fec: remove QUIRK_HAS_RACC from i.mx27
>>   net: fec: align IP header in hardware
>>
>>  drivers/net/ethernet/freescale/fec_main.c | 15 ++++++++++++---
>>  1 file changed, 12 insertions(+), 3 deletions(-)
>>
>> --
>> 2.7.4
> I will investigate the diff between 4.1 and 4.8. Thanks.
> 

Thanks. Note that I'm not sure if the difference is 4.1 vs. 4.8 or
i.MX6UL vs. i.MX6Q.

> Acked-by: Fugang Duan <fugang.duan@nxp.com>
>