Re: [LAD] timers

I forgot to add that snd_hrtimer is used by jackd.
If I turn jackd off, the snd_hrtimer module is not used:

$ lsmod | grep timer
snd_hrtimer 2148 0 ## <<< not used
snd_timer 17408 3 snd_hrtimer,snd_seq,snd_pcm

J.

--- On Sat, 11/7/09, James Warden <warjamy@email-addr-hidden> wrote:

> From: James Warden <warjamy@email-addr-hidden>
> Subject: Re: [LAD] timers
> To: "Emanuel Rumpf" <xbran@email-addr-hidden>, "Ralf Mardorf" <ralf.mardorf@email-addr-hidden-dsl.net>
> Cc: linux-audio-dev@email-addr-hidden
> Date: Saturday, November 7, 2009, 7:34 AM
> Hi guys,
>
> Here is what I have:
>
>
> $ cat /proc/asound/timers
> G0: system timer : 1000.000us (10000000 ticks)
> G3: HR timer : 0.001us (1000000000 ticks)
>   Client sequencer queue 0 : running
> P1-0-0: PCM playback 1-0-0 : SLAVE
> P1-0-1: PCM capture 1-0-1 : SLAVE
>
> Ralf, you do not benefit from a high res timer. See how
> much more precise the HR timer is from the output above.
> Check which snd timer you have loaded:
>
> $ lsmod | grep timer
>
> snd_hrtimer         
>    2148  1
> snd_timer             
> 17408  3 snd_hrtimer,snd_seq,snd_pcm
>
> Of course, your h/w should have a HR timer:
>
> $ ll /dev/hpet
> crw-rw---- 1 root audio 10, 228 2009-11-05 12:59 /dev/hpet
>
> you can specify the clock source to jackd:
>
> $ jackd --help
> ...
> [ --clocksource OR -c [ c(ycle) | h(pet) | s(ystem) ]
> ...
>
>
>
> J.
>
>
> --- On Sat, 11/7/09, Ralf Mardorf <ralf.mardorf@email-addr-hidden-dsl.net>
> wrote:
>
> > From: Ralf Mardorf <ralf.mardorf@email-addr-hidden-dsl.net>
> > Subject: Re: [LAD] timers
> > To: "Emanuel Rumpf" <xbran@email-addr-hidden>
> > Cc: linux-audio-dev@email-addr-hidden
> > Date: Saturday, November 7, 2009, 7:04 AM
> > Emanuel Rumpf wrote:
> > > Hi
> > >
> > > 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@email-addr-hidden:~$ 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
> > _______________________________________________
> > Linux-audio-dev mailing list
> > Linux-audio-dev@email-addr-hidden
> > http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev
> >
>
>
>      
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>

      
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Received on Sat Nov 7 16:15:02 2009