[LAD] [64studio-users] MIDI jitter

[Paul Davis]

On Fri, Jul 2, 2010 at 6:12 AM, Adrian Knoth <adi at drcomp.erfurt.thur.de> wrote:
> On Thu, Jul 01, 2010 at 07:43:38PM -0400, Paul Davis wrote:
>
>> > [[see also latency test results for USB 1.0 devices Emagic MT-4 and
>> > Edirol UM-2, below reply]]
>>
>> just for comparison, here are the results for an RME Digiface:
>> sudo /usr/bin/alsa-midi-latency-test -w -r -R -i 20:0 -o 20:0
>
> You're both missing an argument after -w. I wonder (but haven't
> checked the source) why the tool even starts when you don't provide the
> value for the wait time.

New results:

sudo /usr/bin/alsa-midi-latency-test -w 20 -r -R -i 20:0 -o 20:0
> alsa-midi-latency-test 0.0.3
> set_realtime_priority(SCHED_FIFO, 99).. done.
> clock resolution: 0.000999848 s
> interval between measurements: 20.000 .. 40.000 ms

> sampling 10000 midi latency values - please wait ...
> press Ctrl+C to abort test

sample; latency_ms; latency_ms_worst
     0;       1.00;       1.00
     6;       1.00;       1.00
  9999;       1.00;       1.00
> done.

> latency distribution:
  0.0 -  0.1 ms:        4 #
...
  1.0 -  1.1 ms:     9996 ##################################################

> SUCCESS

 best latency was 0.00 ms
 worst latency was 1.00 ms, which is great.