topic ethernet low performance with imx.6 connected to gigabit ethernet switch in i.MX Processors

ethernet low performance with imx.6 connected to gigabit ethernet switch

reinholdfrederi — Tue, 24 Jun 2014 12:56:39 GMT

Hi,

I use Linux 3.0.35_4.1.0 to imx.6 quad core (Congatec-qmx6) and PHY KSZ9021.Module is connected to Marvell 88E6176 Gigabit Ethernet switch via RMII.

Tests are realized with iperf.

Step1: PC1 to PC2 via switch

PC1 <----> Port2 | Switch Gigabit | Port3 <-----> PC2 : 998 Mbits/s

5 tests complete

Step2: PC1 to Imx-6 without switch

PC1 <----> Imx-6 : 490 Mbits/s

5 tests complete

Step3: PC1 to Imx-6 via switch

PC1 <----> Port2 | Switch Gigabit | Port3 <-----> Imx-6 : 205 Mbits/s

First test is complete.

Second test ethernet communication frezzing.

The ethernet switch works properly with 2 PC's at 998 Mbits/s.

A patch already exist to fix this behavior in Linux drivers (FEC ?) ?

Thanks for your response.

Re: ethernet low performance with imx.6 connected to gigabit ethernet switch

SergioSolis — Tue, 24 Jun 2014 18:41:31 GMT

Please take a look at the following errata for the i.MX6

http://cache.freescale.com/files/32bit/doc/errata/IMX6DQCE.pdf

errata number: ERR004512

It explains about the gigabit ethernet limitation of the i.MX6

Re: ethernet low performance with imx.6 connected to gigabit ethernet switch

reinholdfrederi — Thu, 26 Jun 2014 07:21:16 GMT

"Step2: PC1 to Imx-6 without switch

PC1 <----> Imx-6 : 490 Mbits/s

5 tests complete"

=> it's performance of errata number: ERR004512

"Step3: PC1 to Imx-6 via switch

PC1 <----> Port2 | Switch Gigabit | Port3 <-----> Imx-6 : 205 Mbits/s

First test is complete.

Second test ethernet communication frezzing."

Performance in step3 is not equal to step2.

Re: ethernet low performance with imx.6 connected to gigabit ethernet switch

alxdc — Tue, 01 Jul 2014 13:22:33 GMT

Hi,

could you tell me which module version do you have and which u-boot and kernel patch level? I would recommend you to use the latest one.

thanks,

alex.

Re: ethernet low performance with imx.6 connected to gigabit ethernet switch

reinholdfrederi — Tue, 06 Jan 2015 10:42:46 GMT

"Step2: PC1 to Imx-6 without switch

PC1 <----> Imx-6 : 490 Mbits/s

5 tests complete"

=> it's performance of errata number: ERR004512

"Step3: PC1 to Imx-6 via switch

PC1 <----> Port2 | Switch Gigabit | Port3 <-----> Imx-6 : 205 Mbits/s

First test is complete.

Second test ethernet communication frezzing."

Performance in step3 is not equal to step2.

Partially resolved:

The flow of control has been activated (Marvell Switch Hardware configuration) and now the performance is equal to the errata for the linux kernel 3.0.35 kernel but not for 3.10.17.

Kernel 3.0.35: PC to IMX6: 460 Mbit/s

Kernel 3.10.17: PC to IMX6: 280 Mbit/s