koppi/alsa-midi-latency-test

Measure the roundtrip time of MIDI messages.

alsa-midi-latency-test

alsa-midi-latency-test measures the roundtrip time of a MIDI message in the alsa subsystem of the Linux kernel using a high precision timer. It calculates the worst case roundtrip time of all sent MIDI messages and displays a histogram of the roundtrip time jitter:

Install from source code

git clone https://github.com/koppi/alsa-midi-latency-test.git
cd alsa-midi-latency-test/

The following packages are required to build alsa-midi-latency-test:

sudo apt -y install debhelper autotools-dev automake libasound2-dev

Compile alsa-midi-latency-test as follows:

sh autogen.sh
./configure
make

Install alsa-midi-latency-test as follows:

sudo make install

or build and install an Ubuntu / Debian package:

sudo apt -y install devscripts
debuild -uc -us
sudo dpkg -i ../alsa-midi-latency-test*.deb

– Tested on Ubuntu 22.04

Run alsa-midi-latency-test

• $ alsa-midi-latency-test -l

  Lists available MIDI input and output ports.

• $ alsa-midi-latency-test -i [input port] -o [output port]

  This runs the benchmark with the given input and output port. Note, that the input and output ports have to be connected using a MIDI cable in the real hardware to loop the MIDI message back.

• $ man alsa-midi-latency-test

  The man page contains documentation for all available command line switches.

Benchmark Results

Please share your results in the Wiki.

Definitions

• Wikipedia EN - Latency in engineering
• Wikipedia EN - Latency with audio

See also

• http://lists.linuxaudio.org/listinfo/linux-audio-tuning

  The linux-audio tuning (LAT) mailing list is to help GNU/Linux distribution maintainers and other interested users to share information on system performance tuning matters, especially with regard to real-time Linux kernels.

• http://www.alsa-project.org/

  The Advanced Linux Sound Architecture.

• http://www.evc-soft.nl/evc/products/miditest/

  The MidiTest software for Microsoft Windows.

• https://github.com/raboof/realtimeconfigquickscan

  Linux configuration checker for systems to be used for real-time audio.

• https://codeberg.org/rtcqs/rtcqs

  rtcqs, pronounced arteeseeks, is a Python port of the realtimeconfigquickscan project.

Thanks

• to Arnout Engelen - raboof for initial testing and giving feedback.
• to Clemens Ladisch - cladisch for a number of fixes with the high precision timer and alsa midi event handling.
• to Giulio Moro - giuliomoro for code cleanup and various fixes and support for UART I/O.

BUGS and AUTHORS

Please report bugs to the authors.

• Jakob Flierl - koppi

-- November, 2009, last updated Jan 2023.