ralf.mardorf at alice-dsl.net
Sat Nov 7 12:04:16 UTC 2009
Emanuel Rumpf wrote:
> I'm confused about all the timers.
> There is:
> - system timer
> - hpet (high precision event timer)
> - hr-timer (high resolution timer)
> - rtc (real time clock)
> - cyclic (what's that? a coded loop?)
> - anything else ?
> What is the relation of all these ?
> Which hardware devices are actually used by those ?
> Which is the prefered timer for sequencing ? hr-timer / rtc ?
If hardware is fine with Linux real-time audio, if I understand
correctly, the preferred timer for MIDI sequencers is (should be) system
timer at ! 1000 Hz ! For my hardware, that has got problems with
real-time audio, it's PCM playback and PCM capture. Using this timers
MIDI jitter will decrease a little bit.
This is the output I get for 64 Studio 3.0-beta3:
spinymouse-sudo at 64studio:~$ cat /proc/asound/timers
G0: system timer : 1000.000us (10000000 ticks)
P0-0-0: PCM playback 0-0-0 : SLAVE
P0-0-1: PCM capture 0-0-1 : SLAVE
Client sequencer queue 0 : stopped
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