It’s no so long since I started with FreeRTOS, running on cortex M3 (more specifically I’m on a STM32L151xB).
Following common sense, the conditions under which I expect advantage in using the FreeRTOS real time scheduler is that the average scheduler run time should be much less than the period between two consecutive sysTicks interrupts (leaving enough of the time slice to tasks). In my own mindset the only way I can currently think of to perform such an assessment is to measure duration of the xPortSysTickHandler(), for example starting a timer at the beginning of it and stopping it at the end in order to read out the duration. Does this make any sense? Or, is there anything else you would recommend as quick check or as rule of thumb?