Processor : IMX6Q (MCIMX6Q6AVT10AD)
Linux Kernel : 4.9.11
Kernel reference : wandboard_imx_4.9.11_1.0.0_ga
- We are making IMX6Q based product. In our product we use USB modems for data transmission.
- In IMX6Q there are 4 Cortex-A9 cores. What we observe is mostly all the interrupts are coming on CPU0 core.
- Theoretically it should equally distribute to all the cores.
- I search and read about interrupt affinity. LXR / The Linux Cross Reference and tried change affinity mask (smp_affinity) for the process which is responsible for data transmission.
- But what I observe is event though I changed mask (smp_affinity) it not distributed to all the cores it always fall on any CPU at a time.
- Default affinity mask (smp_affinity) value is "0xF" which is correct to distribute interrupts on all the four cores but behavior is different.
- Question is why this mask has no effect? Am I missing anything?
- Second observation is not all the process are have smp_affinity mask. May I know what is reason behind it?
Any suggestion/direction/comment would be appreciated.