Hello, as the FIQ is faster than IRQ. Are there any specific values about hou much faster?
For example, A53, 1.5G HZ, How many cycles or time can we save if use FIQ instead of IRQ?
That terminology is a legacy from Armv7-A and earlier processors, which did have features to accelerate FIQ over standard IRQ (additional banked registers etc).This is the AArch32 programmers model.
On an Armv8-A or later processor, such as Cortex-A53, in Aarch64 state, there isn't really any timing difference between these. Rather they are used to separate different classes of interrupt source. See "Security Model" at the below:https://developer.arm.com/documentation/198123/0302/Arm-GIC-fundamentals