High CPU Usage even if unused

[vctender]

Hi all,

I recognized an issue in a RPI3 using bt speaker to use the Pi as an audio transceiver. First of all, bt-speaker is working fine without problems. I do not use the builtin WLAN module to avoid the sound problems.

After some time, even if not used, the python-process of bt-speaker constantly causes high cpu usage (100% on one core). How can I help to investigate?

Regards,

[lukasjapan]

Hmmm,
maybe a first step would try to find out if the load comes from inside the C library or python.
Probably it comes from python if the load is also high when not playing audio.

Approaches I could think of are:

• Add debug logging in code
• Monitor the DBUS for abnormalities

Maybe its even GLib responding unnecessarily to something.

Personally I never experienced (or noticed) that issue since I use the Pi exclusively for bluetooth in my project.

[gonzotek]

I am experiencing this as well. It seems to happen shortly after the first bluetooth disconnect after a boot; at least for me. I'm running bt-speaker on a RPi 3 using an up-to-date retropie image (installed retropie 4.2, then updated setup script and retropie packages using retropie's updater). Also using ethernet, wifi is disabled via /boot/config.txt; I am using the onboard bluetooth however.

[vctender]

Restarting bt_speaker resolves the issue immediately. I can confirm that it happens after disconnecting. Nevertheless the service seems to work fine, even with high cpu usage.

[lukasjapan]

I can confirm it now.

Will definitely look into this and try to fix it tonight or tomorrow.

It looks like the raw_audio function is called in an infinite loop, probably with empty data.
A simple sleep should fix this if there is no better solution.

[vctender]

n1, will validate your changes soon. Thanks

[lukasjapan]

Turns out that bluez does not tell to release the filedescriptor of the audio stream on disconnect and the GObject listener went crazy.

It should be fixed now.

[gonzotek]

Confirmed fixed for me (retropie 4.2 base image, packages all up-to-date as of 2017-07-16). Thanks!! Working great :-)

[vctender]

confirmed - Thanks!