On Wed, 2011-04-06 at 12:14 +0200, Alessio Igor Bogani wrote: > Dear Ralf, > > 2011/4/6 Ralf Mardorf <ralf.mard...@alice-dsl.net>: > [...] > > Note that today we should prefer the tickless timer. > [...] > > The 1000 Hz timer still isn't obsolet, because HPET/HR timer sometimes > [...] > > How have you tested? What results have you obtained? If you want > convince someone else you should provide testing procedures and > numeric results.
If I play a MIDI track with external MIDI equipment, DX7, Matrix-1000, D4, TG33 and others with 1000 Hz timer and record it to an audio track and watch the files by Audacity, I can see that there's more jitter, than when using the HR timer. I also recorded kick, hi hat and snare one after the other and the rhythm didn't groove anymore. On LAD, 64 Studio lists, perhaps JACK devel and others too I posted tests years ago. All regarding to this issue and other sync issues, because Linux lacks on sync. > > [...] > > What is my point? > > > > RT on Linux isn't 'hard RT', so de facto even the RT patch isn't a real > > RT patch. > > I think that no one here is interested to determine how much the > PREEMPT_RT patch is "hard" or "soft". We are working on a kernel that > better fits our users needs. > Soft real-time isn't usable for good music. This is an issue for every PC OS (not for oldish computers like the C64 or Atari ST, they are hard real-time capable). Of cause, comparing Steinberg and Linux by a MIDI file on the same machine, it's audible that Linux is far behind a Steinberg PC. I did test this on my computers a long time ago and can't repeat this tests, because I don't like to install Windows again. > In any case the -rt/-realtime kernel maintainer role is vacant. Are > you interested? Hm? I guess I don't have enough knowledge to do that, OTOH I've seen repositories with RT kernels where debugging options where enabled, that warned to 'slow down' real-time. AND I'm not able to build the kernel-rt in a way, that I can add the proprietary NVIDIA graphics driver. I'm thinking of writing a better script to build the next kernel RT and to post it again. > > Ciao, > Alessio Cheers! Ralf -- Ubuntu-Studio-users mailing list Ubuntu-Studio-users@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-studio-users