Re: [LAU] RTC/HPET timer permissions

On 11/27/2012 12:38 PM, Ralf Mardorf wrote:
> On Tue, 2012-11-27 at 11:40 +0100, Jeremy Jongepier wrote:
>> Software like Qtractor can use it too when the module is loaded. Is
>> this recommended? Does it improve MIDI timing for instance? How does
>> it compare to the default timer setting?
>
> If you use hardware MIDI the different PCM timers or
> hr timer can improve jitter or sync between audio and MIDI or whatever,
> at least it results in different drift for MIDI and audio, if you record
> e.g. one MIDI channel after the other using hardware MIDI.
>

What do you mean by hardware MIDI? External synths? So when only using
soft synths using snd-hrtimer doesn't make any difference at all?

> Usually system timer (default) is the best way to go,
> hr timer is better, but can cause issues,

What kind of issues?

  PCM timer should be less good,
> but there could be some voodoo when using it, that could improve things.
>
> If you don't use hardware MIDI don't care about it and use default,
> resp. system timer.
>
> This is what I experienced. Sometimes people fall out a plane when
> flying very high, without a parachute and they survive. There's no
> rational explanation.
>
> "Default" is default for good reasons, to have other options can help,
> but if you don't have issues, there's no reason to care about those
> optional timers.
>

For me there's another reason, it's not about personal use. I just want
to know how this timer stuff actually works so that I can update the
timers section on the linuxmusicians.com Wiki in such a way that it
makes sense. It's now a bit jibber jabber because I actually have no
real clue how all these different timers affect the Linux audio experience.

Regards,

Jeremy

> Regards,
> Ralf
>
>
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Received on Tue Nov 27 16:15:02 2012