[Jack-Devel] Call for testing of MIDI Drivers in JACK 2
Over the past few weeks, Stéphane and I have been overhauling the code
for the MIDI drivers in JACK 2. This includes the Linux FFADO driver,
the Mac CoreMIDI driver, the Windows WinMME driver, and a new Linux
'alsarawmidi' slave driver that can run alongside other master drivers
(i.e. FFADO). The new code is now in JACK 2 SVN, and will probably be
officially released with JACK 1.9.8.
I'm interested in getting feedback on the new drivers, and refining
the code before JACK 1.9.8 is released. I'd like to know how the
drivers work with all sorts of hardware, and with lots of different
JACK configurations. In particular, I'd like to get data about MIDI
latency and (more importantly) jitter that occurs with different
setups. To this end, I've written a program that's distributed as an
example client with JACK 2 named `jack_midi_latency_test` that I'll
talk about in a moment.
If you run JACK 2 from SVN, have a JACK compatible MIDI interface, and
are interested in helping out, here's what you can do:
1.) Start JACK in a terminal. If you're using the CoreMIDI, WinMME,
or alsarawmidi drivers, then use the '-X' switch to specify
'coremidi', 'winmme', or 'alsarawmidi' respectively. For example:
jackd --sync -P70 -Xalsarawmidi -ddummy
2.) Plug a MIDI cable into a MIDI out port and a MIDI in port on your
MIDI interface. On a separate terminal, run `jack_midi_latency_test`.
Usage:
devin@development:~/sandbox$ jack_midi_latency_test --help
Usage: jack_midi_latency_test [options] out-port-name in-port-name
-h, --help print program usage
-m, --message-size=size set size of MIDI messages to send
-s, --samples=n number of MIDI messages to send
-t, --timeout=seconds wait time before giving up on message
In my tests with the 'alsarawmidi' driver, I've been using the
following command line:
jack_midi_latency_test -m 3 -s 8192 -t 5 "system:ESI M8U XL MIDI 4
out" "system:ESI M8U XL MIDI 4 in"
Make sure that the out-port-name and the in-port-name match the names
corresponding to the ports where you just plugged in your MIDI cable.
:)
3.) Send me the results. I'd like to know the name of your MIDI
interface, the protocol it uses to communicate with your computer
(USB, PCI, etc.), and the results of `jack_midi_latency_test`. Also,
let me know if your system isn't configured for realtime.
Here's an example of what I'd like to see:
----------
MIDI interface: ESI M8U XL (USB)
JACK command: jackd --sync -P70 -Xalsarawmidi -ddummy
devin@development:~/sandbox$ jack_midi_latency_test -m 3 -s 8192 -t 5
"system:ESI M8U XL MIDI 4 out" "system:ESI M8U XL MIDI 4 in"
Reported out-port latency: 21.31-21.31 ms (1023-1023 frames)
Reported in-port latency: 21.31-21.31 ms (1023-1023 frames)
Average latency: 44.48 ms (2131.46 frames)
Lowest latency: 43.93 ms (2105 frames)
Highest latency: 45.35 ms (2173 frames)
Peak MIDI jitter: 1.42 ms (68 frames)
Average MIDI jitter: 0.25 ms (11.46 frames)
Jitter Plot:
0.0 - 0.1 ms: 1701
0.1 - 0.2 ms: 1660
0.2 - 0.3 ms: 1513
0.3 - 0.4 ms: 1626
0.4 - 0.5 ms: 1549
0.5 - 0.6 ms: 140
0.6 - 0.7 ms: 2
0.8 - 0.9 ms: 1
Latency Plot:
43.9 - 44.0 ms: 225
44.0 - 44.1 ms: 795
44.1 - 44.2 ms: 813
44.2 - 44.3 ms: 715
44.3 - 44.4 ms: 871
44.4 - 44.5 ms: 849
44.5 - 44.6 ms: 823
44.6 - 44.7 ms: 857
44.7 - 44.8 ms: 767
44.8 - 44.9 ms: 830
44.9 - 45.0 ms: 610
45.0 - 45.1 ms: 35
45.1 - 45.2 ms: 1
45.3 - 45.4 ms: 1
Messages sent: 8192
Messages received: 8192
----------
(Note: The peak jitter above is the difference between the highest
latency and the lowest latency. The jitter plot is created using the
differences between the individual latency of each message, and the
overall average latency. If you see a bug in the latency test
program, please let me know so I can fix it.)
If you have more than on MIDI interface and/or want to test with
multiple JACK configurations, then that would be awesome and totally
appreciated.
As of now, I've tested the 'alsarawmidi' driver with an Edirol UM-1S
USB and an ESI M8U XL, and the FFADO driver with an Edirol FA-101.
Stéphane has tested the CoreMIDI driver with his E-Magic MT4, and the
WinMME with the Maple Virtual MIDI cable driver.
I (nervously) look forward to your feedback. :)
Thanks in advance,
--
Devin Anderson
devin (at) charityfinders (dot) com
CharityFinders - http://www.charityfinders.com/
synthclone - http://synthclone.googlecode.com/
1302129032.6125_0.ltw:2,a <BANLkTi=COogwJ0sf8TgqLnktV+8Fdw2hzA at mail dot gmail dot com>