[LAD] ALSA MIDI latency test results are far away from reality

Niels Mayer nielsmayer at gmail.com
Thu Jul 15 17:07:10 UTC 2010


On Wed, Jul 14, 2010 at 6:23 AM, Ralf Mardorf
<ralf.mardorf at alice-dsl.net> wrote:
> For the MIDI audio test's LXDE session I'm running GNOME terminal tab 1
> JACK2, tab 2 Qtractor. Evolution offline + this Email opened for writing
> to the lists. Envy24 Control and nothing else.
>
> For Qtractor I switched from queue timer (resolution) 'system timer
> (1000 Hz)' to 'HR timer (1000000000 Hz)' and restarted Qtractor.

For your prior failures, are you sure you had the correct soundcard
setup as the MIDI queue timer?
This caused me some issues in the past:
http://old.nabble.com/the-defacto-host-for-lv2-tt28789821.html#a28793953

Now my Qtractor View->Options->MIDI->Playback-Queue Timer is
permanently set to HR timer which avoids such issues when switching
soundcards.

You may want to check this setting prior to running tests... I also
found this thread helpful w/r/t explaining timer issues in MIDI:
http://old.nabble.com/Is-ALSA-using-hrtimer--ts28699922.html

-- Niels



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