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

Question asked by Frederic RVE on Jun 24, 2014
Latest reply on Jan 6, 2015 by Frederic RVE



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.