23 Feb
2011
23 Feb
'11
8:28 p.m.
On 02/23/2011 11:22 AM, Olivier Guilyardi wrote:
Hi,
On 02/17/2011 10:53 PM, Robin Gareus wrote:
It only does iff the audio-I/O thread (or process) is executed with
realtime privileges (`man chrt` - man `pthread_setschedparam` ).
if you have a RT_PREEMPT kernel you can also raise the priority of the
audio-device interrupt handler.
Well, it's a bit more complex than that.. not sure if you can go that
way on Android easily.
/proc/sys/kernel/sched_rt_runtime_us
/proc/sys/kernel/sched_rt_period_us
<kernel-source>/Documentation/scheduler/sched-rt-group.txt
There's something which confuses me. But I'm not sure how this realtime period
settings relate to the audio I/O period. 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