Export CPU less then 100%


I notice that during export my CPU usage is far less then 100%. I know that I have seen it higher. I’m running Ardour 6.9.0 on Kubuntu linux. A snippet of the console output:

Ardour6.9.0 (built using 6.9 and GCC version 6.3.0 20170516)
Ardour: [INFO]: Your system is configured to limit Ardour to 1048576 open files
Ardour: [INFO]: Loading system configuration file /mnt/ExtraHome/wilbert/Audio/Ardour-6.9.0/etc/system_config
Ardour: [INFO]: Loading user configuration file /home/wilbert/.config/ardour6/config
Ardour: [INFO]: CPU vendor: GenuineIntel
Ardour: [INFO]: AVX-capable processor
Ardour: [INFO]: CPU brand: Intel(R) Core™ i7-3770K CPU @ 3.50GHz
Ardour: [INFO]: Using AVX optimized routines

I’m not asking for ‘The Answer’, as I am aware that I’m likely not providing sufficient information. The question actually is: what else should I check to find out the cause? (Btw, the export duration is still very acceptable, but it was faster… :wink:

Below some ‘config’ information is copied as retrieved from the About box.


Build documentation: False
Debuggable build: False
Export all symbols (backtrace): False
Install prefix: /usr
Strict compiler flags: []
Internal Shared Libraries: True
Use External Libraries: False
Library exports hidden: True
Free/Demo copy: False

ALSA DBus Reservation: True
Architecture flags: None
ARM NEON support: False
Aubio: True
AudioUnits: False
Build target: x86_64
Canvas Test UI: False
Beatbox test app: False
CoreAudio: False
CoreAudio 10.5 compat: False
Debug RT allocations: False
Debug Symbols: False
Denormal exceptions: False
Dr. Mingw: False
FLAC: True
FPU optimization: True
FPU AVX/FMA support: True
Freedesktop files: False
Libjack linking: weak
Libjack metadata: True
Lua Binding Doc: False
Lua Commandline Tool: True
LV2 UI embedding: True
LV2 support: True
LV2 extensions: True
LXVST support: True
Mac VST support: False
NI-Maschine: False
OGG: True
Phone home: True
Process thread timing: False
Program name: Ardour
Samplerate: True
PT format: True
PTW32 Semaphore: False
Threaded WaveViews: True
Translation: True
Unit tests: False
Use LLD linker: False
VST3 support: True
Windows VST support: False
Wiimote support: False
Windows key: Mod4><Super

PortAudio Backend: False
CoreAudio/Midi Backend: False
ALSA Backend: True
Dummy backend: True
JACK Backend: True
Pulseaudio Backend: True

Buildstack: 652e628
Mac i386 Architecture: False
Mac ppc Architecture: False
Mac arm64 Architecture: False

This is perfectly normal.

If you have just one track and a 8 core CPU, export can only use 1 core, and you see 12.5% CPU usage for 100% DSP load (if you export faster than realtime).

If you have multiple Tracks and Busses, it depends how those are connected and how many can be processed in parallel. Usually the bottleneck is the master bus (which cannot be processed in parallel), so you will never see a full 100% CPU utilization on a multi-core system.

Hi Robin,

That makes sense. As I learned more, I started to use busses more extensively. So in that, I might indeed have introduced some bottlenecks.