On Wed, Apr 09, 2008 at 02:40:04PM -0700, Fernando Lopez-Lezcano wrote: > > All this said, I personally haven't hit any issues with things like MIDI in > > Fedora where the -rt kernel would have helped me. Maybe my gear is special, > > but latency between me hitting a key on a synth and having that note show > > up in rosegarden, and a sound being created is well below perceivable. > > And that would be how many milliseconds? I honestly couldn't say (it's been some time, and I'm a few thousand miles from home right now). > What could seem below the perception level to you (caveat: I don't know > if you are a musician and what instrument you play) may bother a > professional percussionist using the computer as an instrument. It all > depends on your demands as a performer. "musician" may be stretching my abilities somewhat :) But yes, I understand that I'm probably not pushing things perhaps as far as some others may be. > Besides realtime performance, all the audio-over-the-network being done > at CCRMA needs it (see: http://ccrma.stanford.edu/groups/soundwire/). > > This is, in a nutshell, multichannel (between 4 and 8 channels) > non-compressed high quality bidirectional audio being sent between 2 or > 3 geographically separate locations to create a virtual concert hall and > jam session or concert. You don't want to add _any_ latency to the one > that speed of light already gives us :-) We routinely run at 64 frames > (or 128 if the links are not good). The stock Fedora kernel is just not > good enough although I'm sure it is getting better all the time. *nod*. A while ago, I was tempted to add the latency-tracer part of -rt to Fedora kernels just to see what would show up, but Ingo wasn't really interested because he felt that we'd get a lot of reports we'd already fixed in -rt. The fundamental changes to spinlocks is probably the real controversial stuff that's left to go upstream. How well that goes remains to be seemn over the coming months. > > Right now the guys working on that stuff typically have a > > bunch of 'boring' test cases more tailored towards replicating situations > > like stock trades and the like. If we can construct additional use-cases > > I'm sure Ingo, Thomas & co would be very interested to hear about them. > > Especially if these cases are triggering different latency paths. > > The apps being worked on at CCRMA (jacktrip) would touch both the > network drivers and drivers for pro audio cards. Probably disk as well > if the same host is being used to record the performance in Ardour. Ok, that's an interesting use-case and in honesty, I don't think it's too different to the use-cases like the stock trading stuff that people have been focusing on, so it's understandable why you're reaping the same rewards. Dave -- http://www.codemonkey.org.uk _______________________________________________ Fedora-music-list mailing list Fedora-music-list@xxxxxxxxxx http://www.redhat.com/mailman/listinfo/fedora-music-list
