[hatari-devel] Profiling Hatari code with Valgrind (was: Major changes in DSP code)

laurent.sallafranque at free.fr laurent.sallafranque at free.fr
Thu Dec 30 09:25:57 CET 2010


Hi,

I'll have a look at all of this next year ;)

For your crossbar question, the answear is no.

Crossbar is a data transfer "component" between 4 inputs and outputs (DMA, DSP,
Mic and Extern DSP). You can transfer everything you want, not only sound.

For example, the 4K demo "NoCrew: Aggressive Party 2" uses DSP play / DMA record
in handshake mode to display the tridi screen. (It's referenced in the
compatibility list)

So, the crossbar has to run continuously.

About the crossbar, as I sais in a previous message, I think there's a problem
which would explain many DSP problems : the frequency of the crossbar has t obe
precise and constant, but because of instructions like DIV, MUL, MOVEM, ... we
can miss some clocks, which would explain why sometimes, sound is so dirty.
I'll make a specific thread about this problem soon).

I know there'a also a problem in the SSI part when DSP transfers datas in 16
bits and DMA gets the datas in 8 bits. I'll have to fix this.

I'll have a look at your dsp.c patch soon.

Best regards,

Laurent


Selon Eero Tamminen <oak at helsinkinet.fi>:

> Hi,
>
> On torstai 30 joulukuu 2010, Eero Tamminen wrote:
> > Attached is a screenshot of Kcachegrind output on 30l_coke.prg.
> > With some other program the hotspots could be elsewhere, it's always
> > good idea to profile several programs.
>
> For example for wildfire.prg, the profile looks like the attached one.
>
> Btw. In this and previous one I'm a bit surprised by Crossbar interrupt
> handler part.  These 4kB DSP demos don't have any sound and isn't Crossbar
> supposed to be involved only(?) with sound?
>
>
> 	- Eero
>





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