14 Jul
2010
14 Jul
'10
5:11 p.m.
On Wed, 2010-07-14 at 15:52 +0200, Clemens Ladisch wrote:
I've got 1 USB MIDI and two PCI MIDI by 2 Terratec EWX 24/96 Envy24
based sound cards. I'll avoid to ever connect the USB MIDI to my machine
again (as I'll avoid to install ever a Windows to it again ;).
Next month I could buy another MIDI adaptor cable and run
alsa-midi-latency-test by using both PCI cards.
I bring myself to connect the USB MIDI one more time ;).
64 Studio 3.3 alpha
$ su -c "poff dsl-provider"
$ su -c "cpufreq-selector -g performance"
$ uname -a
Linux 64studio 2.6.31-2-multimedia-amd64 #1 SMP PREEMPT RT Thu Oct 1
16:14:20 BST 2009 x86_64 GNU/Linux.
$ alsa-midi-latency-test -l
Port Client name Port name
14:0 Midi Through Midi Through Port-0
16:0 TerraTec EWX24/96 TerraTec EWX24/96 MIDI
20:0 USB Device 0x170b:0x11 USB Device 0x170b:0x11 MIDI 1
24:0 TerraTec EWX24/96 TerraTec EWX24/96 MIDI
########################################################################
### ONE OF THE PCI CARDS
########################################################################
$ alsa-midi-latency-test -Rrw=5 -i16:0 -o16:0
Ralf Mardorf wrote:
Qtractor at the moment is ALSA MIDI only and I even didn't use the -Xseq
bridge.
1.
I disconnected all audio connections for JACK and connected hw MIDI in
to hw MIDI out.
Is this connection through JACK or through ALSA, i.e., does it show up
in the output of "aconnect -l"? From what I understand, JACK's sample-
synchronous timing always adds latency, and might add period-related
jitter depending on the implementation. Yamaha DX7
--> Alesis D4 results in a 100% musical groove.
Yamaha DX7 --> PC --> Alesis D4 results in extreme latency,
With a single MIDI loopback cable, the latency test program tests
a "PC --> PC" connection. A more realistic test would be
"PC1 --> PC2 --> PC1" (or just one PC if it has two inputs and two
outputs). alsa-midi-latency-test 0.0.3
set_realtime_priority(SCHED_FIFO, 99).. done.
clock resolution: 0.000000001 s
sampling 10000 midi latency values - please wait ...
press Ctrl+C to abort test
sample; latency_ms; latency_ms_worst
0; 1.05; 1.05
787; 1.06; 1.06
1227; 1.06; 1.06
8738; 1.07; 1.07
9999; 1.00; 1.07
done.
latency distribution:
...
1.0 - 1.1 ms: 9992
##################################################
1.1 - 1.2 ms: 8 #
SUCCESS
best latency was 0.99 ms
worst latency was 1.07 ms, which is great.
########################################################################
### THE USB MIDI WITH AN UNLUCKY ENTRY FOR THE RTIRQ SCRIPT
########################################################################
Usually I keep Rui's entries for the script.
$ cat /etc/default/rtirq | grep RTIRQ
RTIRQ_NAME_LIST="rtc snd i8042"
RTIRQ_PRIO_HIGH=98
RTIRQ_PRIO_DECR=5
RTIRQ_RESET_ALL=0
RTIRQ_NON_THREADED="rtc snd"
# RTIRQ_HIGH_LIST="timer"
$ alsa-midi-latency-test -Rrw=5 -i20:0 -o20:0
alsa-midi-latency-test 0.0.3
set_realtime_priority(SCHED_FIFO, 99).. done.
clock resolution: 0.000000001 s
sampling 10000 midi latency values - please wait ...
press Ctrl+C to abort test
sample; latency_ms; latency_ms_worst
0; 2.21; 2.21
9999; 1.99; 2.21
done.
latency distribution:
...
1.9 - 2.0 ms: 2 #
2.0 - 2.1 ms: 9997
##################################################
...
2.2 - 2.3 ms: 1 #
SUCCESS
best latency was 1.95 ms
worst latency was 2.21 ms, which is great.
########################################################################
### PCI MIDI out --> USB MIDI in
########################################################################
$ alsa-midi-latency-test -Rrw=5 -i20:0 -o16:0
alsa-midi-latency-test 0.0.3
set_realtime_priority(SCHED_FIFO, 99).. done.
clock resolution: 0.000000001 s
sampling 10000 midi latency values - please wait ...
press Ctrl+C to abort test
sample; latency_ms; latency_ms_worst
0; 2.03; 2.03
186; 2.04; 2.04
2726; 2.04; 2.04
9999; 1.99; 2.04
done.
latency distribution:
...
1.9 - 2.0 ms: 2 #
2.0 - 2.1 ms: 9998
##################################################
SUCCESS
best latency was 1.92 ms
worst latency was 2.04 ms, which is great.
########################################################################
### USB MIDI out --> PCI MIDI in
########################################################################
$ alsa-midi-latency-test -Rrw=5 -i16:0 -o20:0
alsa-midi-latency-test 0.0.3
set_realtime_priority(SCHED_FIFO, 99).. done.
clock resolution: 0.000000001 s
sampling 10000 midi latency values - please wait ...
press Ctrl+C to abort test
sample; latency_ms; latency_ms_worst
0; 1.14; 1.14
1; 1.93; 1.93
2; 1.99; 1.99
5; 2.00; 2.00
6; 2.00; 2.00
13; 2.01; 2.01
22; 2.03; 2.03
36; 2.03; 2.03
51; 2.03; 2.03
65; 2.03; 2.03
265; 2.04; 2.04
1160; 2.04; 2.04
2267; 2.07; 2.07
9999; 1.96; 2.07
done.
latency distribution:
...
1.1 - 1.2 ms: 1 #
...
1.9 - 2.0 ms: 31 #
2.0 - 2.1 ms: 9967
##################################################
2.1 - 2.2 ms: 1 #
SUCCESS
best latency was 1.14 ms
worst latency was 2.07 ms, which is great.
$ cd /etc/init.d
$ ./rtirq status
PID CLS RTPRIO NI PRI %CPU STAT COMMAND
388 FF 95 - 135 0.0 S< irq/8-rtc0
1119 FF 90 - 130 0.0 S< irq/21-ICE1712
1115 FF 89 - 129 0.0 S< irq/20-ICE1712
381 FF 85 - 125 0.0 S< irq/1-i8042
380 FF 84 - 124 0.0 S< irq/12-i8042
102 FF 50 - 90 0.0 S< irq/9-acpi
539 FF 50 - 90 0.0 S< irq/16-ohci_hcd
588 FF 50 - 90 0.0 S< irq/19-ehci_hcd
590 FF 50 - 90 0.0 S< irq/22-ahci
601 FF 50 - 90 0.0 S< irq/14-ide0
603 FF 50 - 90 0.0 S< irq/17-ohci_hcd
604 FF 50 - 90 0.0 S< irq/22-ohci1394
608 FF 50 - 90 0.0 S< irq/18-ohci_hcd
611 FF 50 - 90 0.0 S< irq/17-ohci_hcd
614 FF 50 - 90 0.0 S< irq/18-ohci_hcd
943 FF 50 - 90 0.0 S< irq/7-parport0
1670 FF 50 - 90 0.2 S< irq/18-nvidia
1984 FF 50 - 90 0.0 S< irq/26-eth0
4 FF 49 - 89 0.0 S< sirq-high/0
5 FF 49 - 89 0.0 S< sirq-timer/0
6 FF 49 - 89 0.0 S< sirq-net-tx/0
7 FF 49 - 89 0.0 S< sirq-net-rx/0
8 FF 49 - 89 0.0 S< sirq-block/0
9 FF 49 - 89 0.0 S< sirq-tasklet/0
10 FF 49 - 89 0.0 S< sirq-sched/0
11 FF 49 - 89 0.0 S< sirq-hrtimer/0
12 FF 49 - 89 0.0 S< sirq-rcu/0
18 FF 49 - 89 0.0 S< sirq-high/1
19 FF 49 - 89 0.0 S< sirq-timer/1
20 FF 49 - 89 0.0 S< sirq-net-tx/1
21 FF 49 - 89 0.0 S< sirq-net-rx/1
22 FF 49 - 89 0.0 S< sirq-block/1
23 FF 49 - 89 0.2 S< sirq-tasklet/1
24 FF 49 - 89 0.0 S< sirq-sched/1
25 FF 49 - 89 0.0 S< sirq-hrtimer/1
26 FF 49 - 89 0.0 S< sirq-rcu/1
- Ralf
Regards,
Clemens