How to debug when IRQs are disabled for few milliseconds?

[priyaranjan]

Hello All,

I'm having issues on DRA7x based Android system. We have seen that
that when we use 'cat' command in shell to dump some debug trace
the 'shell' get scheduled in CPU0 and sometimes in CPU1. IRQs get
blocked in the system for the amount of time the Shell runs. We have
captured systrace which shows the same. Since we have some stringent
requirement to service the IRQs within 2 miliisecond
approx, we are missing the IRQs for important peripherals like Audio.

I have tried the Hard lockup but the threshold can be programmed
minimum to 1second hence could not succeed in this.
I have also tried to use ftrace, however it was very difficult to find
out where exactly the IRQs are getting disabled.

Can anyone help?

Regards,
Priyaranjan