General Support - Kanotix realtime (with kernel preemption patch)?

hifi25nl - 15.05.2006, 22:21 Uhr
Titel: Kanotix realtime (with kernel preemption patch)?
I have now an ...almost realtime sound system with a "patched PAM". Latency is very low the most of time (always less than 0.1 ms) but every few minutes I am losing some frames in my Rosegarden4 sequencer (jack is telling me about Xruns of 4-8 ms). I have tried the old lsm realtime module with the same results and I have applied all the tweaks to jack that I have found on the web.

I have seen somewhere in this forum that maybe is possible to install in Kanotix a kernel with Ingo Molnar preemption patch for realtime. However the procedure is not simple (at least for me) and I think is possible to apply the patch only to vanilla kernels.

Why not offer a special Kanotix realtime kernel in alternative to the standard one?

slh - 15.05.2006, 22:34 Uhr
Titel: Kanotix realtime (with kernel preemption patch)?
Who is going to do the work for an immature kernel patch that does have serious stability and portability issues - besides preventing quite a few h/w drivers from working, especially considering it as a fact that 90% of all users and none of the developers have any use for rt?

Realtime is counterproductive and actually slower in most use cases except audio/ video mastering (not editing), even if the available patches were remotely stable. Just applying Ingo Molnar's patch doesn't necessarily decrease latencies as such, there is more tweaking required which would need a dedicated developer personally interested in audio mastering techniques and who can actually "feel" the effects of different settings.
kenyee - 15.05.2006, 23:18 Uhr
Titel: Kanotix realtime (with kernel preemption patch)?
It also makes the nVidia drivers flaky...there's a long thread on nvnews on this...
mzilikazi - 16.05.2006, 20:14 Uhr
Titel: RE: Kanotix realtime (with kernel preemption patch)?
I use a realtime kernel. It wasn't so hard to build. Get the vanilla source, apply Ingos patch, (and any others you need) and away you go. Build a Debian kernel. If you like I can let you try my kernel but I will warn you that it doesn't have all of the patches that the Kanotix kernel has since I personally don't need several of them. You may also need to build some drivers depending on your hardware. I do not post this kernel anywhere as a download for this reason. I simply do not have the time to maintain a kernel or make sure that everyone's everything is working.

Nvidia drivers work fine here on a FX5600 w/ the realtime kernel and xruns are a thing of the past.
In fact, I can compile a kernel and listen to music simutaneously without a single xrun. Winken
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