I can supply no quantifications for the 32 bit 2.6.20-16-realtime kernel in ubuntustudio other than no xruns have been observed. With the low latency kernel, xruns were observed. Jack is the only app that has a -20 priority assigned. The general workstation has been running without fault. The general Debian / Ubuntu philosophy tends towards system stability. Tom On Wednesday 03 October 2007 14:54:32 Fernando Lopez-Lezcano wrote: > On Wed, 2007-10-03 at 18:39 +0200, Frank Barknecht wrote: > > Hallo, > > > > Matthias Schönborn hat gesagt: // Matthias Schönborn wrote: > > > I've just read that there's a difference between a realtime-kernel and > > > the low-latency-kernel provided by ubuntustudio. The text in the german > > > wiki on ubuntuusers.de said, that a realtime-kernel is slightly better > > > than the lowlatencykernel (http://wiki.ubuntuusers.de/Echtzeitkernel) - > > > then why isn't it used in ubuntustudio? Or do I just mix something up? > > > > I think, this wiki and maybe Ubuntustudio as well are using a very > > confusing terminology. > > > > Generally we have two kinds of kernels: The "vanilla" kernel as > > downloadable on kernel.org and the same kernel, but patched with Ingo > > Molnars RT-patches. The vanilla kernel, if configured properly with > > CONFIG_PREEMPT etc., already gives very good performance in the low > > latency department, enough for many users, even audio users. I run one > > of these. > > > > If you want more, then you can install a RT-patched kernel, as is > > provided in the linux-rt or linux-realtime packages. I would call the > > Ingo-Molnar-patched kernels Realtime-Kernels or Low-Latency-Kernels. > > To further clarify (or confuse?) the issue, how "low latency" the kernel > is also depends on how you configure the kernel build options before or > after patching the kernel with Ingo's patch. For Ingo's patch > CONFIG_PREEMPT_RT is the best option in terms of latency but there are > others (CONFIG_PREEMPT_DESKTOP) that have a more conservative approach > but have (relatively speaking) higher latencies. So from worst to best > it would be something like: > > vanilla linuz + CONFIG_PREEMPT_NONE > vanilla + CONFIG_PREEMPT_VOLUNTARY (used by the stock Fedora kernel) > vanilla + Ingo + CONFIG_PREEMPT_DESKTOP > vanilla + Ingo + CONFIG_PREEMPT_RT (the one I use for Planet CCRMA) > > (there's more granularity and options in the CONFIG_PREEMPT* world but > those are the ones that have the biggest impact as far as I can > remember) > > -- Fernando > > > _______________________________________________ > Linux-audio-user mailing list > Linux-audio-user@xxxxxxxxxxxxxxxxxxxx > http://lists.linuxaudio.org/mailman/listinfo.cgi/linux-audio-user _______________________________________________ Linux-audio-user mailing list Linux-audio-user@xxxxxxxxxxxxxxxxxxxx http://lists.linuxaudio.org/mailman/listinfo.cgi/linux-audio-user
