Thousands Of Alsa Buffer Underruns In Puae?


silver

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Oct 12, 2008
Messages
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I've compiled the latest version (2.3.1) of Gnostic's PUAE from the git here:
https://github.com/GnoStiC/PUAE

(Gnostic has thrown in a pandora build script now. It uses SDL sound; I can't get it to build with ALSA sound available in the source.

I'm compiling direct on the pandora. After installing and updated a large number of libraries via opkg, it builds and runs and after some config file messing (GUI is fairly broken).

Things work fairly well, but as soon as any sound is produced I get a colossal number of ALSA errors:

Code:
ALSA lib pcm.c:7234:(snd_pcm_recover) underrun occured

This appears to hit performance and cause stutter. Altering latency/buffering options have no impact.

As this error has been seen a lot before, but attributed to the incorrect sound clock polarity fixed last year by notaz, I thought I would ask for tips on where to start addressing this. I'm running HF5 beta2.

EDIT: It's possible that the underruns are due to emulation being too slow. Overclocking to 1GHz appears to have minimal impact though, so either it's still too slow or something else?
 
You have a buffer underrun if the audio buffer is not filled fast enough, so of course, overclocking reduces the amount of underruns.
Another way to remove the underruns is to increase the buffer, but that adds a bit of delay to the sound.
 
I'll investigate some more, maybe do some profiling.

I don't have this issue on other SDL based emulators that run too slow. E.g mame.
 
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