[LAU] [OT] Kernel 2.6.39.1

On Tue, 2011-06-07 at 22:50 +0200, Robin Gareus wrote:
> BTW. IIRC you should not use the -X... options for JACK-midi but rather
> use a2j instead. AFAIK there were/are [timing?] issues with the built-in
> JACK midi backends. (see Jeremy's workshop slides on how to launch a2j
> using qjackctl's "Execute Script" option.)
>
> HTH,
> robin

Yesno! Perhaps it's better to avoid -Xseq, but I'm using JACK2 from svn
with -Xalsarawmidi + a2jmidi_bridge to get a jitter free hw MIDI output
of Qtractor's ALSA MIDI. I don't believe latency tests, but I believe
what I hear and what I see for the waveforms. No jitter! Before Jack2
from svn I experienced 1 - 3 ms jitter for hw MIDI (ALSA), depending to
the used MIDI interface, I can't make music even with 1ms jitter, I'm
able to hear this, see the following from jack devel list:

On Sat, 2011-06-04 at 03:54 +0200, Ralf Mardorf wrote:
Similar good results as before :)
>
> Cheers!
>
> Ralf
>
> Current Debian testing 64-bit
> Two TerraTec EWX24/96 PCI
> One RME HDSPe AIO PCI express
>
> # svn up /usr/src/jackmp
> At revision 4447.
> # chgrp audio /dev/hpet
> # chmod g+rw /dev/hpet
> # modprobe snd-hrtimer
>
> $ uname -a
> Linux debian 2.6.33.9-rt31 #1 SMP PREEMPT RT Thu Jun 2 12:42:46 CEST
> 2011 x86_64 GNU/Linux
>
> $ jackd --sync -Xalsarawmidi -dalsa -r48000 -p256
> 'system:midi_capture_1', alias='system:1-1 HDSPM MIDI 1 1 in'
> 'system:midi_capture_2', alias='system:1-2 HDSPM MIDI 2 1 in'
> 'system:midi_capture_3', alias='system:2-1 TerraTec EWX24/96 MIDI 1
in'
> 'system:midi_capture_4', alias='system:3-1 TerraTec EWX24/96 MIDI 1
in'
> system:midi_playback_1', alias='system:1-1 HDSPM MIDI 1 1 out'
> system:midi_playback_2', alias='system:1-2 HDSPM MIDI 2 1 out'
> system:midi_playback_3', alias='system:2-1 TerraTec EWX24/96 MIDI 1
out'
> system:midi_playback_4', alias='system:3-1 TerraTec EWX24/96 MIDI 1
out'
>
> CPU frequency scaling performance
>
> $ jack_midi_latency_test -m 3 -s 8192 -t 5 "system:1-1 HDSPM MIDI 1 1
> out" "system:1-1 HDSPM MIDI 1 1 in"
> Waiting for connections ...
> Waiting for test completion ...
>
> Reported out-port latency: 5.33-5.33 ms (256-256 frames)
> Reported in-port latency: 5.33-5.33 ms (256-256 frames)
> Average latency: 12.23 ms (559.04 frames)
> Lowest latency: 12.21 ms (558 frames)
> Highest latency: 12.30 ms (562 frames)
> Peak MIDI jitter: 0.09 ms (4 frames)
> Average MIDI jitter: 0.01 ms (0.18 frames)
>
> Jitter Plot:
> 0.0 - 0.1 ms: 8192
>
> Latency Plot:
> 12.2 - 12.3 ms: 8192
>
> Messages sent: 8192
> Messages received: 8192
> $ jack_midi_latency_test -m 3 -s 8192 -t 5 "system:2-1 TerraTec
EWX24/96
> MIDI 1 out" "system:2-1 TerraTec EWX24/96 MIDI 1 in"
> Waiting for connections ...
> Waiting for test completion ...
>
> Reported out-port latency: 5.33-5.33 ms (256-256 frames)
> Reported in-port latency: 5.33-5.33 ms (256-256 frames)
> Average latency: 12.23 ms (558.97 frames)
> Lowest latency: 12.21 ms (558 frames)
> Highest latency: 12.29 ms (562 frames)
> Peak MIDI jitter: 0.09 ms (4 frames)
> Average MIDI jitter: 0.00 ms (0.05 frames)
>
> Jitter Plot:
> 0.0 - 0.1 ms: 8192
>
> Latency Plot:
> 12.2 - 12.3 ms: 8192
>
> Messages sent: 8192
> Messages received: 8192
>
> Old install, Edubuntu Maverick 32-bit on the same machine, just two
> TerraTec EWX24/96 PCI, no PCI express
> Test output copied from
>
http://lists.jackaudio.org/private.cgi/jack-devel-jackaudio.org/2011-April/007423.html
>
> revision 4290
> Linux edubuntu 2.6.33.7.2-rt30 #1 SMP PREEMPT RT Sun Jan 30 21:00:46
CET
> 2011 i686 GNU/Linux
>
> $ jackd --sync -Xalsarawmidi -dalsa -r48000 -p256
>
> $ jack_midi_latency_test -m 3 -s 8192 -t 5 "system:TerraTec EWX24/96
> MIDI out" "system:TerraTec EWX24/96 MIDI in"
> Reported out-port latency: 5.33-5.33 ms (256-256 frames)
> Reported in-port latency: 5.33-5.33 ms (256-256 frames)
> Average latency: 11.06 ms (530.95 frames)
> Lowest latency: 11.04 ms (530 frames)
> Highest latency: 11.10 ms (533 frames)
> Peak MIDI jitter: 0.06 ms (3 frames)
> Average MIDI jitter: 0.00 ms (0.02 frames)
>
> Jitter Plot:
> 0.0 - 0.1 ms: 8192
>
> Latency Plot:
> 11.0 - 11.1 ms: 8189
> 11.1 - 11.2 ms: 3
>
> Messages sent: 8192
> Messages received: 8192

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Received on Wed Jun 8 04:15:02 2011