Re: [LAU] Is ALSA using hrtimer?

From: Grant <emailgrant@email-addr-hidden>
Date: Sun May 30 2010 - 21:02:40 EEST

>> I have hrtimer support compiled into my kernel, but when I watch 'top'
>> while music is playing I can see that 'timer' uses CPU cycles but
>> 'hrtimer' never does.  How can I find out if ALSA is using hrtimer?
>
> ALSA uses the sound card interrupt for timing.  The hrtimer is used only
> for MIDI playback and for sound cards without interrupts, such as the
> SuperH, i.MX, PC Speaker, and dummy devices.

Are you sure? CONFIG_SND_HRTIMER says:

"ALSA uses the hrtimer as a precise timing source. The ALSA sequencer
code also can use this timing source."

Would ALSA use the sound card interrupt for timing with my USB DAC?

- Grant
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Received on Mon May 31 00:15:03 2010

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