This version of FreeRTOS has been modified by Espressif to be SMP-aware. The API is similar to the original FreeRTOS API, with the following changes: - The xTaskCreate() function now creates tasks that will run on the first core only, for backwards compatibility. To schedule tasks on another core, use xTaskCreatePinnedToCore(), which will accept a core ID as the last argument. If this is the constant tskNO_AFFINITY, the task will be dynamically scheduled on whichever core has time. - vTaskSuspendAll/vTaskResumeAll in non-SMP FreeRTOS will suspend the scheduler so no other tasks than the current one will run. In this SMP version, it will only suspend the scheduler ON THE CURRENT CORE. That is, tasks scheduled to run on the other core(s) or without a specific CPU affinity, will still be able to run. - Enabling and disabling interrupts will only affect the current core. Disabling the interrupts will not disallow other tasks to run as it would on a single-core system: the other core still will keep on executing all it's own. Use a mux, queue or semaphore to protect your structures instead. - This FreeRTOS version has the task local storage backported from the 8.2.x versions. It, however, has an addition: you can also set a callback when you set the pointer. This callback will be called by the idle task, with the pointer as an argument, when the thread is destroyed. This depends on the idle task getting CPU time; when a thread is hogging the CPU without yielding, the idle thread won't be called and the delete callback won't be called either.