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[Help] Audio crackles when CPU is under heavy load and music is in the background (programming.dev)
submitted 2 days ago* (last edited 2 days ago) by ludrol@programming.dev to c/linux4noobs@programming.dev
14 comments fedilink hide all child comments
 

Any linux wizards know why when my sound sources go to background and CPU is under heavy load the audio crackles?

apps tested: minecraft, vlc(flatpak), spotify(flatpak), other fltapaks
crackles on both bluetooth and minijack headphones,
disabling microphone, easyeffects, gpu screen recorder ( gsr-default_output) didn't help

I use blender to put the load on CPU but it also happens when compiling or gaming

I have increased stuff in cat /etc/pipewire/pipewire.conf 

[…]
## Properties for the DSP configuration.
    default.clock.rate          = 192000
    #default.clock.allowed-rates = [ 48000 ]
    default.clock.quantum       = 1024
    default.clock.min-quantum   = 32
    default.clock.max-quantum   = 4096
[…]

pw-top -b
S   ID  QUANT   RATE    WAIT    BUSY   W/Q   B/Q  ERR FORMAT           NAME 
S   29      0      0   
***
   
***
 
***
 
***
    0                  Dummy-Driver
S   30      0      0   
***
   
***
 
***
 
***
    0                  Freewheel-Driver
S   45      0      0   
***
   
***
 
***
 
***
    0                  Midi-Bridge
S   48      0      0   
***
   
***
 
***
 
***
    0                  bluez_midi.server
R   52   2048 192000  10,6ms  69,7us  0,99  0,01  453    S32LE 2 48000 alsa_output.pci-0000_06_00.6.analog-stereo
R  213    900  48000 229,0us  69,1us  0,02  0,01    0    F32LE 2 48000  + Firefox
R  219      0      0  13,0us  41,1us  0,00  0,00    0    F32P 2 192000  + easyeffects_sink
R  217      0      0    +++   17,0us  +++   0,00  428                   + ee_soe_output_level
R  174      0      0   9,3ms  34,3us  0,88  0,00  5416                   + ee_soe_spectrum
R  206    512  48000 300,5us  54,3us  0,03  0,01    0    F32LE 2 48000  + java
R  186    900  48000 359,5us  56,2us  0,03  0,01    0    F32LE 2 48000  + Firefox
R  242    900  48000 417,2us  52,4us  0,04  0,00    0    F32LE 2 48000  + Firefox
R  129    960  48000 152,1us  74,5us  0,01  0,01    0    S16LE 2 48000  + gsr-default_output
R  116   1920  48000 472,4us  62,5us  0,04  0,01    0    F32LE 2 48000  + VLC media player (LibVLC 3.0.23)
I   53   4096 192000   8,9us   3,3us  0,00  0,00  109   S32LE 2 192000 alsa_input.pci-0000_06_00.6.analog-stereo
S   68      0      0   
***
   
***
 
***
 
***
    0                  v4l2_input.pci-0000_06_00.3-usb-0_3_1.0
I  191      0      0   0,0us   0,0us  ???   ???     0    F32LE 2 48000 Firefox
I  216      0      0   0,0us   0,0us  ???   ???     0    F32LE 2 48000 Firefox
I  220      0      0   0,0us   0,0us  ???   ???     0    F32LE 2 48000 Firefox
S  244      0      0   
***
   
***
 
***
 
***
    0                  Blender
I  205      0      0   0,0us   0,0us  ???   ???     0    F32LE 2 44100 spotify
R  249   2048 192000  10,7ms  35,5us  1,00  0,00  1339    S16LE 1 48000 alsa_input.usb-145f_Trust_GXT_242_Microphone-00.mono-fallback
R  120      0      0  12,2us  13,5us  0,00  0,00    7    F32P 2 192000  + easyeffects_source
R  145      0      0   6,2us   8,2us  0,00  0,00   90                   + ee_sie_output_level
R  230      0      0   5,7us   7,6us  0,00  0,00  118                   + ee_sie_spectrum
R  144    960  48000  18,9us  49,7us  0,00  0,00    0    S16LE 2 48000  + gsr-default_input
R  257      0      0 122,2us    +++   0,01  +++   1101                   + ee_sie_rnnoise
R  106      0      0  44,8us 139,8us  0,00  0,01  236                   + ee_sie_stereo_tools
R   84      0      0   
***
   8,6us 
***
  0,00  235                   + ee_sie_crossfeed
R  158      0      0   5,3us   7,8us  0,00  0,00   30                   + ee_sie_reverb
R  171      0      0   5,2us   8,9us  0,00  0,00    4                   + ee_sie_equalizer
S  172      0      0   
***
   
***
 
***
 
***
    0                  plasmashell
S  119      0      0   
***
   
***
 
***
 
***
    0                  plasmashell
S  233      0      0   
***
   
***
 
***
 
***
    0                  ee_test_signals
S  193      0      0   
***
   
***
 
***
 
***
    0                  plasmashell
I  175      0      0   0,0us   0,0us  ???   ???     0    F32LE 2 48000 plasmashell

I know to little to dig into the scheduler stuff. systemctl status rtkit-daemon prints about pipewire sucess at priority 20.

I am on KDE/linux (bazzite based on fedora atomic44)

--------------
OS: Bazzite x86_64
Host: 82JU (Legion 5 15ACH6H)
Kernel: Linux 7.1.3-ogc3.4.fc44.x86_64
Uptime: 4 hours, 46 mins
Packages: 2 (appimage), 4 (brew), 1 (brew-cask), 173 (flatpak), 3014 (rpm)
Shell: bash 5.3.9
Display (BOE08E8): 1920x1080 in 16", 120 Hz [Built-in]
DE: KDE Plasma 6.7.2
WM: KWin (Wayland)
WM Theme: leaf-dark-color
Theme: Fusion (LeafDark) [Qt], Vapor [GTK2/3]
Icons: breeze-dark [Qt], breeze-dark [GTK3/4]
Font: Noto Sans (10pt) [Qt], Noto Sans (10pt) [GTK3/4]
Cursor: Teto (30px)
Terminal: konsole 26.4.3
CPU: AMD Ryzen 5 5600H (12) @ 4.28 GHz
GPU 1: NVIDIA GeForce RTX 3060 Mobile / Max-Q [Discrete]
GPU 2: AMD Radeon Vega Series / Radeon Vega Mobile Series [Integrated]
Memory: 12.05 GiB / 13.49 GiB (89%)
Swap: 16.62 GiB / 35.59 GiB (47%)
Disk (/): 49.00 MiB / 49.00 MiB (100%) - overlay [Read-only]
Disk (/etc): 845.89 GiB / 929.93 GiB (91%) - btrfs
Local IP (tun0): 10.96.0.42/16
Battery (L20M4PC0): 100% [AC Connected]
Locale: pl_PL.UTF-8
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[–] ludrol@programming.dev 1 points 5 hours ago

I have ruled out the RAM issue by running as simplified test as possible: spotify + stress-ng and easy effects not running

free -h
               total        used        free      shared  buff/cache   available
Mem:            13Gi       7,8Gi       851Mi       166Mi       5,9Gi       5,7Gi
Swap:           35Gi       2,3Gi        33Gi

I have started to dig more into the perf, trace-cmd and cyclictest and finally managed to run all of the in the same time to capture the same high delay event. If the arch forum is correct then pipewire uses data-loop.0 process for realtime processing. It got SCHED_RR, so it seems correct as according to man pages it would preempt the SCHED_OTHER that stress-ng runs in.

Interesting thing I (and a council of clankers) noticed in trace_cpu_4.txt is that the interrupt didn't fire at specified time, and when it did, scheduler immediately preempted stress-ng to run the cyclictest as it's SHED_FIFO.

My current theory is some sort interrupt problem

trace-cmd report > trace.txt sed -n '2682652,2684299p' trace.txt > trace_extract.txt cat trace_extract.txt | grep -i "\[004\]" > trace_cpu_4.txt

logs:

ps -eo pid,class,rtprio,ni,pri,comm -L | grep -i 'rr\|ff\|dln'
     19 FF      99   - 139 migration/0
     21 FF      50   -  90 idle_inject/0
     24 FF      50   -  90 idle_inject/2
     25 FF      99   - 139 migration/2
     30 FF      50   -  90 idle_inject/4
     31 FF      99   - 139 migration/4
     36 FF      50   -  90 idle_inject/6
     37 FF      99   - 139 migration/6
     42 FF      50   -  90 idle_inject/8
     43 FF      99   - 139 migration/8
     48 FF      50   -  90 idle_inject/10
     49 FF      99   - 139 migration/10
     54 FF      50   -  90 idle_inject/1
     55 FF      99   - 139 migration/1
     60 FF      50   -  90 idle_inject/3
     61 FF      99   - 139 migration/3
     66 FF      50   -  90 idle_inject/5
     67 FF      99   - 139 migration/5
     72 FF      50   -  90 idle_inject/7
     73 FF      99   - 139 migration/7
     78 FF      50   -  90 idle_inject/9
     79 FF      99   - 139 migration/9
     84 FF      50   -  90 idle_inject/11
     85 FF      99   - 139 migration/11
    104 FF      50   -  90 irq/9-acpi
    108 TS       - -20  39 kworker/R-ata_sff
    112 FF      50   -  90 watchdogd
    115 FF      50   -  90 irq/25-AMD-Vi0-Evt
    116 FF      50   -  90 irq/26-AMD-Vi0-PPR
    117 FF      50   -  90 irq/27-AMD-Vi0-GA
    428 TS       - -20  39 kworker/R-amdgpu_dm_hpd_rx_offload_wq
    430 FF      50   -  90 card1-crtc0
    431 FF      50   -  90 card1-crtc1
    432 FF      50   -  90 card1-crtc2
    433 FF      50   -  90 card1-crtc3
    461 TS       -   0  19 nvidia-modeset/deferred_close_kthread_q
    462 FF      50   -  90 irq/62-nvidia
    475 TS       -   0  19 UVM deferred release queue
    624 FF      50   -  90 irq/63-ELAN06FA:00
    770 FF       1   -  41 psimon
    842 FF       1   -  41 psimon
   1255 FF      50   -  90 irq/96-rtw89_pci
   1513 RR      99   - 139 rtkit-daemon
   1589 FF       1   -  41 psimon
   3098 RR       1   -  41 kwin_wayland
   3098 RR       1   -  41 eDP-1
   3098 RR       1   -  41 libinput-connec
   3114 RR      20   -  60 data-loop.0
   3115 RR      20   -  60 data-loop.0
   3316 RR      20   -  60 data-loop.0
   3316 RR      20   -  60 data-loop.0
   3316 TS       -   0  19 bazaarrunner
   3316 TS       -   0  19 krunner_charrun
   3327 RR      20   -  60 data-loop.0
   6596 TS       -   0  19 WRRende~ckend#1
   6596 TS       -   0  19 WRRende~kend#19
  37282 FF       1   -  41 psimon
  37326 FF      80   - 120 cyclictest
  37326 FF      80   - 120 cyclictest
  37326 FF      80   - 120 cyclictest
  37326 FF      80   - 120 cyclictest
  37326 FF      80   - 120 cyclictest
  37326 FF      80   - 120 cyclictest
  37326 FF      80   - 120 cyclictest
  37326 FF      80   - 120 cyclictest
  37326 FF      80   - 120 cyclictest
  37326 FF      80   - 120 cyclictest
  37326 FF      80   - 120 cyclictest
  37326 FF      80   - 120 cyclictest

sudo cyclictest --mlockall --smp --priority=80 --interval=200 --breaktrace=800
# /dev/cpu_dma_latency set to 0us
policy: fifo: loadavg: 11.16 5.94 3.72 19/2368 37630

T: 0 (37327) P:80 I:200 C: 268947 Min:      8 Act:   13 Avg:   13 Max:     462
T: 1 (37329) P:80 I:700 C:  76837 Min:      8 Act:   15 Avg:   13 Max:      78
T: 2 (37330) P:80 I:1200 C:  44819 Min:      9 Act:   15 Avg:   14 Max:      49
T: 3 (37331) P:80 I:1700 C:  31635 Min:      8 Act:   14 Avg:   14 Max:     153
T: 4 (37332) P:80 I:2200 C:  24443 Min:      9 Act:   15 Avg:   14 Max:     106
T: 5 (37333) P:80 I:2700 C:  19915 Min:      9 Act:   14 Avg:   14 Max:     132
T: 6 (37334) P:80 I:3200 C:  16802 Min:      9 Act:   19 Avg:   14 Max:     766
T: 7 (37335) P:80 I:3700 C:  14531 Min:      9 Act:   15 Avg:   14 Max:     179
T: 8 (37336) P:80 I:4200 C:  12800 Min:      8 Act:   21 Avg:   13 Max:      37
T: 9 (37337) P:80 I:4700 C:  11437 Min:      9 Act:   19 Avg:   14 Max:     264
T:10 (37338) P:80 I:5200 C:  10337 Min:      9 Act:   17 Avg:   14 Max:      73
T:11 (37339) P:80 I:5700 C:   9430 Min:      9 Act:   18 Avg:   14 Max:      83
# Thread Ids: 37327 37329 37330 37331 37332 37333 37334 37335 37336 37337 37338 37339
# Break thread: 37332
# Break value: 2488

sudo perf sched timehist > perf_timehist.txt awk '$1 >= 9980.792239 && $1 <= 9980.797096' perf_timehist.txt > perf_extract.txt https://pastebin.com/iuB98bXg

sudo perf sched latency > perf_latency.txt https://pastebin.com/JP0PfrSU