24 Feb
2011
24 Feb
'11
7:01 p.m.
On 02/24/2011 03:59 PM, Olivier Guilyardi wrote:
Hello Robin,
Now, say I'm only focusing on playback now. Is there something wrong with
calling a blocking output API from a realtime thread as I ask below?
mmh. it depends on how the blocking is done. If it is a spin-lock it
will consume CPU and block other processes which are running at lower
priority in the meantime (but only up to sched_rt_runtime_us per second.
Other processes won't starve). Is there a poll (or select) function
available as part of the libaudio API?
If the i/o block waits for a signal (e.g. IRQ), it will work just fine.
> On
Android, the closest that one can get to hardware in a more or less portable
> way is libaudio [1]. It's Android's audio HAL. This API exposes blocking
read()
> and write() calls, with fixed buffer sizes (input and output buffer sizes
> generally do not match, but that's another problem).
>
> So, this may be a silly/newbie question, but can one access this blocking API
> from a realtime thread? What will happen when it blocks? How does the read/write
> period relate to sched_rt_period_us?
>
> [1] http://source.android.com/porting/audio.html
--
Olivier