IRQ Latency and CPU Use

I am running a system with RT-Preempt kernel v6.4.8-rt8 CPU is 12th Gen Intel(R) Core(TM) i7-12800HE This system is receiving data through the CAN Bus. Every 1 millisecond a burst of 3 messages is received in the hardware CAN interface. Most of the time (99.99998%) of the time the messages are available on the socket to be received within 1ms of the previous group. But once per minute approximately, there is a delay of 4-6 ms in which the messages has been received in the hardware but is not available on the socket when calling recv. Things I have checked: - My application is calling deterministically recv every 1ms, the data is not there. - With candump I get the confirmation that the messages are received every 1 ms by checking the hardware timestamp. - The IRQ associated with the CAN device is bound to a CPU core (2) that is not used by my RT application (CPU core 6) ## The hack If I execute stress --cpu 1 and bind the stress CPU core to the same core as the IRQ the delays disappear. So I assume that a delay in waking up the CPU is causing the culprit. I have tried all of the following to try to keep the CPU awake without using stress. - performance /sys/devices/system/cpu/cpu2/cpufreq/scaling_governor - performance /sys/devices/system/cpu/cpu2/cpufreq/energy_performance_preference - idle=poll intel_idle.max_cstate=0 in /etc/default/grub and update-grub; reboot Still have delays with all these applied. I am out of ideas, I cannot switch to acpi-cpufreq because it does not respect the integrated GPU power consumption (which is not being used during these tests). Any other knobs I can turn to decrease that latency or ways I can understand the root issue?