View Full Version : LMMS and Kernel Packing Curiosity

29th November 2006, 09:26 AM
Hey all,

I'm one of many people who uses Fedora Core to produce music. I'm using FC6, actually. I'm quite happy.

When importing MIDIs into LMMS though, the MIDI is not imported accurately. I was wondering if it was a problem with LMMS (I posted to their mailing list), or if it was due to Fedora Core's kernels, which are high latency. Any ideas on this?

Also, I'm definitely no techie... but I was wondering if plans were in the works for low latency FC kernel packages... something like "kernel-desktop" as opposed to "kernel-laptop".

Thanks for your time, all.

29th November 2006, 09:34 AM
The latest kernel shipped with Fedora has improved latency, though it is not stellar, as it is no RT (you need a specially crafted one for that, with Ingo's RT patches). The preemption is set by default at voluntary (you could get it to low-latency, but you require again, to rebuild the kernel) and now the default internal tick rate is (at a LONG last) set at 1000Hz... I think I'll publish after all that HowTo I've been meaning to write about how to build and compile a low-latency and real-time kernel on Fedora systems using the RPM infrastructure (so you could manage your kernels with rpm).

29th November 2006, 07:45 PM
Sounds like a good idea. I was just thinking that for people who need kernel-specific drivers (kmod-nvidia, etc.), that rebuilding your own kernel could just end up being one heck of a hassle. But I am glad to see that it's finally set to 1000hz.

30th November 2006, 02:37 AM
I actually had some low latency kernels for FC, but did not picked up much steam... I still like lowlatency kernels (in my case for gaming), and the current release is rather good. Still, I'll write up that HowTo. Good thing the main line kernel already includes the lowlatency patches, and you can build a lowlatency kernel with the main line sources.

The nVidia and ATi drivers are not such a problem. As long as you have installed the official kernel in tadem with your modified one, you can use the nvidia installer to build the kernel-side module and continue using your livna-installed driver just fine. Only thing required is to run the nvidia installer with the -K switch to build the kernel module ONLY.