Thank you Emanuel for this thread :) thank you James for the information :)
hopefully this might narrow down my trouble with MIDI jitter for external equipment, OTOH I don't have any MIDI jitter for MIDI internal Linux. ALSA MIDI and JACK MIDI seems to be fine what ever timer I use, this means there is absolutely no jitter when using a Linux sequencer to control a Linux synth. Jitter only occurs when using my USB MIDInterface to control external MIDI equipment. Unfortunately I can't get my Envy24's MPU working. There seems to be no hrtimer available yet: $ lsmod | grep snd_hrtimer $ lsmod | grep timer snd_timer 22024 2 snd_pcm,snd_seq snd 63800 21 snd_ice1712,snd_ak4xxx_adda,snd_cs8427,snd_ac97_codec,snd_i2c,snd_mpu401_uart,snd_usb_audio,snd_pcm_oss,snd_mixer_oss,snd_pcm,snd_hwdep,snd_seq_oss,snd_rawmidi,snd_seq,snd_timer,snd_seq_device $ uname -a Linux 64studio 2.6.29-1-multimedia-amd64 #1 SMP PREEMPT RT Thu Feb 26 16:18:05 UTC 2009 x86_64 GNU/Linux Before I start googleing. Is this a feature for 2.6.31 only? I'm still not able to boot the .31 kernel-rt from the Suse 11.2 RC repository and compiling for Suse also failed, but in the past I never had trouble to build kernel-rt for Debian/ Ubuntu based 64 Studio. Maybe I should try to build a kernel .31 for 64 Studio? Or is it just a module I need to add? Or is my hardware missing something? Going to use Google now. Bye, Ralf James Warden wrote: > 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 <warj...@yahoo.com> wrote: > > >> From: James Warden <warj...@yahoo.com> >> Subject: Re: [LAD] timers >> To: "Emanuel Rumpf" <xb...@web.de>, "Ralf Mardorf" >> <ralf.mard...@alice-dsl.net> >> Cc: linux-audio-dev@lists.linuxaudio.org >> 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.mard...@alice-dsl.net> >> wrote: >> >> >>> From: Ralf Mardorf <ralf.mard...@alice-dsl.net> >>> Subject: Re: [LAD] timers >>> To: "Emanuel Rumpf" <xb...@web.de> >>> Cc: linux-audio-dev@lists.linuxaudio.org >>> 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-s...@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 >>> _______________________________________________ >>> Linux-audio-dev mailing list >>> Linux-audio-dev@lists.linuxaudio.org >>> http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev >>> >>> >> >> _______________________________________________ >> Linux-audio-dev mailing list >> Linux-audio-dev@lists.linuxaudio.org >> http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev >> >> > > > > > -- Secret of Tux: http://images.wallaceandgromit.com/user_uploads/forum_thumbnails/5/75/355.jpg "Gromit bit me" says HMV dog: http://img.dailymail.co.uk/i/pix/2007/03_03/GomitHMVPA_468x319.jpg _______________________________________________ Linux-audio-dev mailing list Linux-audio-dev@lists.linuxaudio.org http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev