[alsa-devel] [PATCH 1/2 v2] ASoC: soc-cache: block based rbtree compression

Mark Brown broonie at opensource.wolfsonmicro.com
Tue May 3 13:02:06 CEST 2011

On Tue, May 03, 2011 at 12:50:03PM +0200, Takashi Iwai wrote:
> Mark Brown wrote:

> > This isn't about CPU usage, it's about I/O bandwidth which is a big
> > concern in situations like resume where you can be bringing the device
> > back up from cold.

> Hm, but how do these patches achieve it?  I see no change in the I/O
> access side.

There's none directly but we need to get the data into blocks before we
can do bulk I/O (or do complicated gather bulk I/O).

> > CPU usage isn't really that much of an issue; we need to burn an awful
> > lot of CPU for it to take longer than the I/O takes.

> Yes, that's why I've been asking it...

We're talking I2C here so you're looking at 400kHz contended buses for
the I/O, though of course optimisations in CPU usage are also useful.

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