Thanks for your detailed explanation and feedback, I am a bit confused about the #4 you mentioned here -> > 4) Affinity of the demultiplex interrupt Are you saying there is a chance to queue this demultiplexing IRQ event to the current running CPU ? would it fall into the first if clause ? > if (desc->target_cpu == smp_processor_id()) { > handle_irq_desc(desc); And that's really an approach worth to try, I will work on it. Thanks