Re: [LAU] A2J-MIDI Bridge error

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To: Kevin Utter <kvutter@...>
Cc: <linux-audio-user@...>
Date: Saturday, December 21, 2013 - 5:04 pm

On Sat, 21 Dec 2013, Kevin Utter wrote:

> The uname -a shows:

I would sugest that installing linux-lowlatency would make a difference as
many of the settings depend on having the access provided in the
lowlatency or RT kernel.

Lowlatency vs. RT:

RT is a patched kernel. It does provide better latency performance, but
there may be some problems with those code chunks needed for video or
wireless etc. On a Ubuntu system you would have to roll you own.

Lowlatency is the same as the generic kernel with one or two config
changes when compiling that allow some preemptive operations like setting
interupt priorities for example. It is precompiled and can be installed
with apt-get, synaptic, The kde variants... who knows, maybe even USC

I have only one audio IF (at least I only use one at a time) and use the
lowlatency kernel. I am able to get less than 1ms latency with no xruns
when I turn off hyperthreading.... of course the audio card itself has 1ms
delay internally that is not included in that :) Anyway, in my case the
RT kernel would not add anything. This is also true for most USB audio IF
as their lowest latency is around 5ms as determined by their smallest
buffer settings. RT kernels might help when using more than one audio card
at a time. Note that a MIDI IF is not an audio card and is treated
separately even if it is a aprt of the same card as the audio IF. The MIDI
port is just a serial port that is treated specially. It is not even that
fast.

--
Len Ovens
www.ovenwerks.net

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Messages in current thread:
[LAU] A2J-MIDI Bridge error, Kevin Utter, (Fri Dec 20, 5:37 pm)
Re: [LAU] A2J-MIDI Bridge error, Jeremy Jongepier, (Fri Dec 20, 6:58 pm)
Re: [LAU] A2J-MIDI Bridge error, Kevin Utter, (Sat Dec 21, 2:59 pm)
Re: [LAU] A2J-MIDI Bridge error, Jeremy Jongepier, (Sat Dec 21, 7:06 pm)
Re: [LAU] A2J-MIDI Bridge error, Jeremy Jongepier, (Sat Dec 21, 7:11 pm)
Re: [LAU] A2J-MIDI Bridge error, Len Ovens, (Sat Dec 21, 5:04 pm)
[LAU] How to turn off hyperthreading?, david, (Sun Dec 22, 6:34 am)
Re: [LAU] How to turn off hyperthreading?, Gene Heskett, (Sun Dec 22, 9:52 am)
Re: [LAU] How to turn off hyperthreading?, Moshe Werner, (Sun Dec 22, 6:57 am)
Re: [LAU] How to turn off hyperthreading?, david, (Sun Dec 22, 7:24 am)
Re: [LAU] How to turn off hyperthreading?, Len Ovens, (Sun Dec 22, 4:37 pm)
Re: [LAU] How to turn off hyperthreading?, Jeremy Jongepier, (Sun Dec 22, 8:04 pm)
Re: [LAU] How to turn off hyperthreading?, Len Ovens, (Sun Dec 22, 11:25 pm)
Re: [LAU] How to turn off hyperthreading?, Len Ovens, (Sun Dec 22, 9:23 pm)
Re: [LAU] A2J-MIDI Bridge error, Paul Davis, (Fri Dec 20, 6:09 pm)
Re: [LAU] A2J-MIDI Bridge error, Ralf Mardorf, (Fri Dec 20, 6:01 pm)