I am trying to do some bench marking of FreeRTOS+FAT SL using Atmel SAM4S and Atmel Studio IDE. I am trying to measure the time required to write to a SD card. For this purpose I am using a simple bit toggling before and after the f_write function. The results are not very clear to me since the timing is not constant all the time. Does someone know how to measure this more accurately or if this is the expected behavior. Moreover, I have a task with a vTaskDelay(1000) and it performs the same writing function over again. Any suggestion or help is appreciated.