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i.MX6Q Ethernet: Low RX performance

Question asked by Clemens Gruber on Feb 3, 2015
Latest reply on Dec 18, 2017 by ranshalit



we are running Linux on a i.MX6Q with a Micrel KSZ9031RNX Gigabit Ethernet PHY but are experiencing performance problems when receiving data.

I read ERR004512 and think that this is a different issue. Transmitting data works fine, but when receiving the throughput maxes out at 136 Mbit/s. Could this be an indicator that some RX buffers are overflown? Is this a known issue and is there a workaround?

Have you any tips what I could do to improve the situation?

Transmit performance maxes out at about 397 Mbit/s at the moment (tested with iperf).


Kernel version: 3.19-rc7 (but we had similar results with version 3.16)

Might be related to: i.MX6Q ENET.REF_CLK input




Best regards,

Clemens Gruber


EDITED: Corrected the problem description. I made a mistake when measuring the throughput. The correct values are 136 Mbit RX and 397 Mbit TX.