Re: Scheduler ( was: Just a second ) ...

[Jeff Garzik <jgarzik@mandrakesoft.com>]

Linus Torvalds wrote:
> Jeff, you've worked on the sb code at some point - does it really do
> 32-byte sound fragments? Why? That sounds truly insane if I really parsed
> that code correctly. That's thousands of separate DMA transfers
> and interrupts per second..

I do not see a hardware minimum fragment size in the HW docs...  The
default hardware reset frag size is 2048 bytes.  So, yes, 32 bytes is
pretty small for today's rate.

But... I wonder if the fault lies more with the application setting a
too-small fragment size and the driver actually allows it to do so, or,
the code following this comment in reorganize_buffers in
drivers/sound/audio.c needs to be revisited:
   /* Compute the fragment size using the default algorithm */

Remember this code is from ancient times...  probably written way before
44 Khz was common at all.

	Jeff


-- 
Jeff Garzik      | Only so many songs can be sung
Building 1024    | with two lips, two lungs, and one tongue.
MandrakeSoft     |         - nomeansno