[alsa-devel] performance between access mothods!

Takashi Iwai tiwai at suse.de
Tue Jul 7 13:26:33 CEST 2009

At Sun, 05 Jul 2009 09:03:23 -0300,
Guilherme Longo wrote:
> Hi all!
> I came across a doubt regarding the the access mode between application 
> and PCM device.
> It is a hardware parameter related property and there are 5 different 
> types available:
> taking in account that these first 3 parameters has direct communication 
> with the memory, that means a higher speed operation?

Yes.  The others are using copy_from/to_user(), so there are slight
overheads by explicit copying.

> And the fact of 
> the interleaved has all the samples mixed together , makes any 
> difference in performance in comparison to the noninterleaved that has 
> samples stored on different buffers?

No.  It's just a difference of what format the hardware supports.


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