In STM32mp157f-dk2 board, sdmmc2 is used for inbuilt wifi over SDIO and I am using sdmmc3 with esp32 chip to connect it to wifi over SDIO. I am able to connect ST board to wifi over sdmmc3 but with iperf it is giving constant throughput of 1 Mbps irrespective of change in max-frequency.
I was going through kernel module in st linux and found that in sdio_card_irq_get function which will be called while claiming sdio irq, it is creating a kernel thread with name ksdioirqs/mmcX. This thread continuously polls for rx data. This kthread has schedule_timeout() function for minimum 1 jiffies. In my case, 1 jiffies = 10msec as CONFIG_HZ=100. So I think because of this schedule_timeout, I am getting less throughput (with change in CONFIG_HZ=1000 throughput is increased). Is it correct behavior? and if yes then why sdmmc2 throughput is 12Mbps for same frequency as sdmmc2? (sdmmc2 and sdmmc3 is using same driver which is mmci.c)
