IMX6 PCIe-RealTek8169 low throughput problem , MTU > 400 not working

Abi__1289 · ‎03-15-2022

Hi,

We are using imx6q chipset having PCIe based Gigabit Ethernet Link , In which we are not able to produce higher throughput even having the possibility upto 2.5 Gbps . If we are using MTU more than 400 we are finding packet loss and packet drop in the data transmission.

Processor - imx6q

PCIe to LAN - RTL8111F-CG (RT8169 device driver).

Would be really helpful for response.

Abi__1289 · ‎03-28-2022

Hi

I found the problem for the PCIe low throughPut Bug. When we are using 4.9 kernel , r8169.c driver is having problem with the MRRS(max read request size) of the PCIe is being set to 4096 . By this the over all link is getting dropped .

Solution : Set the MRRS size to 512 or we can disable the rtl_tx_performance_tweak function will solve the problem in 4.9 version kernel . And In 5.4 kernel the updated r8169_main.c driver is not having this problem.

Thanks ,

Abhishek

View solution in original post

Abi__1289 · ‎03-28-2022

Hi

I found the problem for the PCIe low throughPut Bug. When we are using 4.9 kernel , r8169.c driver is having problem with the MRRS(max read request size) of the PCIe is being set to 4096 . By this the over all link is getting dropped .

Solution : Set the MRRS size to 512 or we can disable the rtl_tx_performance_tweak function will solve the problem in 4.9 version kernel . And In 5.4 kernel the updated r8169_main.c driver is not having this problem.

Thanks ,

Abhishek