The memory used by FreeRTOS will vary depending on configuration, as many features can be removed and buffers resized. See the Space Benchmark Figures for an indication of space used in various configurations.
FreeRTOS makes use of a software interrupt for context switching, and a timer interrupt for the tick mechanism
|Context Switch Interrupt
|System Timer 0
|IVG14 (Interrupt #14)
|TMR (Interrupt #6)
|Core User Software Interrupt 3
Note: An alternative timer can be used by defining configTIMER_INTERRUPT.
Note: On ADSP-2158x/ADSP-SC58x and ADSP-2157x/ADSP-SC57x where anomaly 20-00-0081 applies, then system interrupts SOFT6 (Core1) and SOFT7 (Core2) are used instead of the core interrupt.