On Fri, Feb 27, 2009 at 12:36 AM, <torbenh@xxxxxx> wrote: > On Thu, Feb 26, 2009 at 06:21:48PM -0500, Paul Davis wrote: >> On Thu, Feb 26, 2009 at 4:20 PM, tizo <tizone@xxxxxxxxx> wrote: >> >> > Hi there, >> > >> > Sorry about my previous mail. I was just starting to write a draft >> > about the topics I want to ask, and I accidentally push the send >> > button. >> > >> > Well, my goal is to play two midi keyboards, sending the events >> > through jackd, to qsynth. My computer is a Laptop HP 550, with HDA >> > Intel sound card, 3 GB of memory, and a Core 2 DUO CPU of 1.40 GHz. My >> > OS is UbuntuStudio 8.04, with kernel 2.6.24-23-rt. >> > >> > First of all, I cannot run jackd without xruns, if I configure it with >> > 32 frames per period, or less. I am running it as root, with realtime, >> > and a priority of 70. As soon as I run it, it starts to count xruns, >> > and I am only executing jackd. >> >> >> 32 frames per interrupt is VERY ambitious with an Intel HDA chipset. Its not >> impossible but every single part of your system has to be "just right" for >> this to work. I would start with a less ambitious goal first, and get some >> experience with the setup before trying to get all the way to this latency >> level. >> >> moving to USB will likely make things worse. latencies like this are best >> accomplished with good, prosumer level PCI audio interfaces. > > and most certainly not with a kernel that old. > the old hda drivers are totally broken. > > a quick test on vanilla 2.6.28 shows it runs at -p32 -n3. > but it gives me some xruns when i switch desktop. > -n2 is not possible. i get xrun streams. > I have tried UbuntuStudio 8.10; I can't remember nor the version of the kernel, neither the jack performance, but that kernel had a reported bug, that broke the usb connections with midi keyboards. Maybe I will try another distribution and/or kernel, but that bug has to be fixed for me to be useful. I am running jackd with -n3 too; as you said, with -n3 is not possible. > > -- > torben Hohn > http://galan.sourceforge.net -- The graphical Audio language > _______________________________________________ > Linux-audio-user mailing list > Linux-audio-user@xxxxxxxxxxxxxxxxxxxx > http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user > Thanks very much, tizo _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/mailman/listinfo/linux-audio-user
