Synchronous thread exceeds the time limit by 100 to 200 us when using k_sleep

[aravinth-kalai]

Hello everyone ,

I just created two threads , thread_1 will wake up the thread_2 then thread_1 will goes for sleep by every 20ms , thread_2 will do it's work and it goes for sleep forever , after that thread_1 will resume and the operation will goes on.

void thread_1()
{
    k_wakeup(thread_2_task_id);
    k_msleep(20);
}

void thread_2()
{
    send_CAN_msg(); // execution time is 1ms 
    k_sleep(K_FOREVER);
}

Thread_2 is sending some dummy data to CAN communication , when I see the data in CAN terminal , I can see the cycle time, the cycle time is not same for all time , most of the time it will be 20.1 or 20.2 ms but not exact 20ms.

May I know what's issue is causing the additional 100 to 200us, I measured the execution time of thread_2 it's around 1ms only , but why I'm getting additional 100 to 200us delay, I really want to eliminate the delay , please explain what is causing this delay and how to eliminate the delay .

Thanks in advance !