From: Thomas Jarosch <tomj_at_simonv.com>
Date: Wed, 30 Nov 2011 13:35:37 +0100

Hi,

I just noticed a performance regression with rockbox 3.10
compared to rockbox 3.9 on the Nokia N900.

CPU usage increased by 15 to 20 percent when playing
back a mp3 file. To verify it I downgraded to 3.9,
watched the "top" output and upgraded to 3.10 again,
always playing back the same mp3 file.

Audio playback on maemo 5 is handled by gstreamer / pulseaudio.
I can see an even increase in CPU usage both on the
running rockbox binary and the pulseaudio daemon.

Vague guess: The PCM buffer is passed in smaller chunks
to the OS in 3.10 and therefore causing more handling overhead.

The "buffering thread" values in the debug menu
look similar to me:

 3.9: pcm: x/529200, alloc/real: 7170476
3.10: pcm: x/524288, alloc/real: 5180960


Other ideas what might be wrong?

We should try to figure out if it also affects real hardware targets
or just maemo / other RaaA targets.

Cheers,
Thomas
Received on 2011-11-30