Require Thread permissions in audio primary hal

vinothkumars — Fri, 20 Nov 2020 16:06:15 GMT

Hi All,

I am creating two threads in audio primary Hal with SCHED_FIFO policy but is failing to create the thread, it seems it require SYS_NICE capability. So how to provide CAP_SYS_NICE capability for audio primary Hal. Thanks in advance for the response

Regards,

Re: Require Thread permissions in audio primary hal

weidong_sun — Tue, 24 Nov 2020 03:24:23 GMT

Hi,

I see the code for creating SCHED_FIFO thread in audio hal:

//create rx task, use real time thread.
pthread_attr_init(&attr);
pthread_attr_setschedpolicy(&attr, SCHED_FIFO);
schParam.sched_priority = 3;
pthread_attr_setschedparam(&attr, &schParam);

adev->b_sco_rx_running = true;
ret = pthread_create(&tid_sco_rx, &attr, sco_rx_task, (void *)adev);
It should be fine to imitate this code

In our android audio hal, 2 threads with SCHED_FIFO type will be also created.

[note]

SCHED_FIFO implements a simple, first-in-first-out scheduling algorithm, it does not use time slices.
The SCHED_FIFO level process is scheduled before any SCHED_NORMAL level process. Once a SCHED_FIFO level process is in an executable state, it will continue to execute until it blocks itself or explicitly releases the processor; it is not based on time slices and can be executed forever. Only the higher priority SCHED_FIFO or SCHED_RR task can preempt the SCHED_FIFO task. If there are two or more SCHED_FIFO-level processes, they will execute in turn, but will give up again when they are willing to give up the processor.
As long as a SCHED_FIFO-level process is executing, other lower-level processes can only have a chance to execute after it ends.

Hope this information is helpful to you.

Have a nice day!

B.R,

Weidong

topic Require Thread permissions in audio primary hal in i.MX Processors

Require Thread permissions in audio primary hal

Re: Require Thread permissions in audio primary hal