Second I did the basic security limits:
etc/security/limits.conf @audio - rtprio 99 @audio - memlock 512000 @audio - nice -19
Third I increased the priority of MPD and added the nrpacks latency info to a .sh file:
#!/bin/bash
chrt -f -p 81 $(pidof mpd)
modprobe snd-usb-audio nrpacks=1
Note:place the .sh file in /etc/rc.local
insert path to script [somescript.sh], example —> /home/script.sh
Forth I added my playlists for my favorite web radio stations in the path mpd is searching for so they would show up under Playlists in GMPC
/var/lib/mpd/playlists
Next up I will be looking for processes to kill ie crons etc.
If the Volumio people even look at these forums I sure would like to ask them to put a little effort into house cleaning and making this a “Single Purpose” OS by weeding out unneeded processes etc.
1- Using Swap on SDcards will quickly deteriorate them. I do not suggest to do that
2- Without a RT Kernel you’re not gaining any benefit from setting those limits
3- Setting MPD niceness to -19 tends to make system unstable, and can have bad effects on some systems
4- I did not hear any audible improvements by using nrpacks=1 . Its usage has been deprecated since long time.
But I’m open to discuss them! I tried all the above on Raspberry PI, could be that BBB could benefit on them…
You are on the right path however, improving is always a great things. If you’re looking for some way to improve or change the sound, you could try to tweak some parameter in the kernel. To start, look into
/var/www/command/orion_optimize.sh
You’ll find the 4 kernel profiles, with different files to change in order to edit kernel timings.
This is in my opinion where you could get the most audible results. Try to play with them and we can discuss the results.
It was my understanding that Linux OS’s that run from USB/SD cards don’t use swap. In fact I don’t even think I saw a swap space for the swappiness to be of any use.
Also does the BBB or RPI have functionality for throttling the CPU? I no my Atom processor did not.