Dramatic reduction of system real-time after using igh native driver in Real-Time-Edge for i.MX 8 MM

[BlueZhang]

Hello,

When using the imx8mm-evk-igh.dtb device tree file in an i.MX 8 MM EVK running Real-Time-Edge, the maximum latency measured using cyclictest increases dramatically to more than 700 us. use imx8mm-evk.dtb or remove the following from imx8mm-evk-igh 

compatible = "fsl,imx8mm-fec-igh-native", "fsl,imx8mq-fec-igh-native", "fsl,imx6sx-fec-igh-native"

fields the maximum latency is around 40us.

Test commands used

echo performance > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

cyclictest -p 80 -t5 -m

Thanks.

[Bio_TICFSL]

Hello,

Yes, the imx8mm-evk-igh dtb is for netwroking exclusevely you may have reduced the fps like gpu, and other stuff, if you don't mind better use the imx8mm-evk.dtb.

regards

[BlueZhang]

Hello,
I need to use igh so I have to use imx8mm-evk-igh dtb, testing revealed that the impact on realtime is caused by fsl,imx8mq-fec-igh-native driver, is there any way to eliminate or reduce these effects?
thanks.