msleep accuracy

Hi,
i am testing UART connection between k210 and esp32 on maixduino board. My test code is kendryte-standalone for k210 and arduino for esp32. I am sending simple text every 2000ms (loop with msleep(2000)) and i found that in some cases its shorter than 2000ms between 2 messages:

12:03:56.464 -> text
12:03:58.476 -> text
12:04:00.490 -> text
12:04:02.464 -> text

I dont know yet if this is k210 msleep issue or just arduino logging.

I think it is arduino logging accuracy, you can try any other board like stm32