Interrupt latency in FreeRTOS


I did not find anything in the FreeRTOS documentation about the interrupt latency. The only thing that is written is that an ISR will always pre-empt a task. What I would like to know is if FreeRTOS implements some sort of “zero” interrupt latency like Keil RTX5 or embOS.

And if it does, how is it implemented and is there documentation about it ? In other RTOSes, these zero interrupt latency are not affected by the RTOS tasks and kernel, which also means all the RTOS API is not available from these zero interrupt latency tasks.

Does something like that exist inside FreeRTOS ?

Thanks, best regards

yes, it exists. An ISR running above MAX_SYSCALL priority runs completly out of any interaction with FreeRTOS. Tasks needing to communicate with those ISRs can naturally not use OS services. All of ths is well documented.

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