0

HiFiBerryOS: imagemagick & oom killer

AFS

October 29, 2022 05:29

None

Follow

I recently installed HiFiBerryOS on a 1GB RPi 4. It has been a bit unreliable - music skipping occasionally, and significant lag controlling mpd (over wifi, but with a decent signal). All music is stored locally on the microSD card, so playback shouldn't be affected by the network connection.

In the process of troubleshooting, I noticed that oom killer is killing imagemagick convert processes every couple of minutes. From dmesg:

[Fri Oct 28 22:13:49 2022] Out of memory: Killed process 13115 (convert) total-vm:442584kB, anon-rss:407644kB, file-rss:0kB, shmem-rss:0kB, UID:0 pgtables:872kB oom_score_adj:0

Is this normal behavior, or should I submit a bug? Each killed process using ~400MB of RSS memory, which sounds unreasonably high.

I assume imagemagick is being used to process album art - is there a way I can disable album art entirely? I have already disabled downloading album covers from the internet, but it hasn't fixed the problem.

• Facebook
• Twitter
• LinkedIn

6 comments

• 0
  
  HiFiBerry team October 29, 2022 16:27

  Do you have the "local UI" running? That requires a lot of RAM and you should definitely disable this on a 1GB machine.

• 0
  
  AFS October 30, 2022 16:07

  "Use Connected Display" is not enabled, is that the local UI? I wish I could just switch to a 2GB or 4GB RPi, but it took about six months of waiting before I was able to find a place to buy this 1GB Pi.

  Other than convert eating up RAM every couple of minutes, the rest of the processes are consuming very little memory. Here's a snapshot of the top RAM consumers:

  # ps aux --sort -rss| head -8
  USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
  root       575  7.6  5.3 181568 49216 ?        Ssl  Oct28 191:13 /usr/bin/node /opt/beocreate/beo-system/beo-server.js vv
  root       379  2.3  3.4  82120 32088 ?        Ssl  Oct28  57:50 /usr/bin/python3 /opt/audiocontrol2/audiocontrol2.py
  root       566 95.0  2.3 179364 21964 ?        Rsl  Oct28 2368:27 /bin/mpd --no-daemon
  root       359  0.4  1.3  39592 12544 ?        Ssl  Oct28  11:02 /bin/python3 -m usagecollector.server
  root       386  0.3  1.0  39744  9712 ?        Ssl  Oct28   9:21 python3 /usr/bin/sigmatcpserver --alsa
  root         1  0.0  0.4  30608  3824 ?        Ss   Oct28   1:23 /sbin/init splash
  root       358  1.3  0.3  27788  3436 ?        Ss   Oct28  32:26 /usr/lib/systemd/systemd-journald

  Is there a way I can prevent the convert processes from running entirely? I'm comfortable altering scripts from the command line, but grepping through the various hifiberry scripts I haven't been able to locate whatever is running convert.

  I would estimate that playback skips every 20-80 seconds, and the skips last 0.3 - 2 seconds. I haven't been able to tell if the skips occur exactly when convert is eating up RAM, but it seems likely to be the cause.

  Thanks for your help!

• 0
  
  HiFiBerry team October 31, 2022 06:20

  Try renaming imagemagick to something differently (e.g. imagemagick.old) and see if this helps. However, as it is used to generate thumbnails of albums and artists, the UI for the local music library might not work well.

• 0
  
  AFS November 01, 2022 05:09

  Thanks, that fixed it! Everything works smoothly now - no lag using MPD or SSH, no audio drops. I don't use the web interface, so I'm happy without thumbnails.

  Would it be helpful for me to create an issue on Github for this problem? 400MB+ of RAM consumption to produce a thumbnail seems like it must be unintended behavior.

• 0
  
  HiFiBerry team November 01, 2022 07:38

  Feel free to report a bug. However, I'm not sure if we can easily find an alternative. 

• 0
  
  AFS December 03, 2022 06:04

  I ended up deciding wanted album art. To work around the imagemagick OOM problem, I ran the python script to download the cover art from my desktop instead. On the off change that this would be useful for anyone else with a very large local music collection, here's an outline of the steps in Linux:

  - Install the python mutagen library (I used a python virtual environment)

  - Download hifiberry's musicfiletools repo (https://github.com/hifiberry/musicfiletools)

  - Copy the musicfiletools directory to a python library location (in my case, venv/lib/python3.10/site-packages)

  - Mount the hifiberry local music directory over SFTP: (e.g. sshfs <hifiberry address>:/data/library/music hifiberrymount)

  - Run the getcovers script: python getcovers.py -x <path to hifiberry mount>