[Fedora-music-list] CCRMA kernel in FC5?

[thewade]

Quoting Callum Lerwick <seg at haxxed.com>:

> On Sat, 2006-05-20 at 20:56 -0700, thewade wrote:
>> As far as I know the realtime kernel module, sometimes called the LSM
>> module, is not a part of the mainline Fedora Core kernel(s). Is it now?
>> It used to require a PAM patch and I think a rebuild of the kernel.
>
> From what I remember reading in Kernel Traffic, upstream didn't like the
> LSM approach. They came up with the rlimit approach instead, which has
> been merged upstream and is supported in FC5. That's what we're using in
> jack's README.Fedora.

No no, I am wrong and you are right. I remember this, that rlimits was 
preffered over the LSM module. Great!

>> If I wasn't doing realtime stuff then I would probably agree with you.
>
> How low do you need to go?
>
> On my Athlon 64 3000+ system, I can run jack reliably at a period size
> of 256, on the motherboard's cheezy onboard sound. Any lower and it
> overruns like mad. Which makes sense, according to qjackcontrol that's a
> latency of 10.7ms at 48khz. Given the stock kernel has a 250hz timer,
> that gives you a nyquist scheduling frequency of 125hz, which is a
> period of 8ms. With a stock kernel I don't think we can go any lower
> than 8ms.

I am using and Athalon 64 3400+ in i386 mode because PD doesn't handle 
64 bit tables well yet, and a Hammerfall HDSP card. I would be 
satisified with less then 10ms (I think I am between 5ms and 8ms now) 
because that still allows me to do a large amount of processing without 
too much lag for live performances. Any lower and the numper of 
computations I can do without generating XRUNS decreases. Any higher 
and there starts to be an echo or slapback effect when I play live 
(which sadly doesnt happen much these days).

> I think that's probably good enough for most users. Maybe CCRMA can
> continue to supply kernels for those who demand more. Now if only I
> could get Rosegarden to stop complaining...

I haven't used rosegarden. Its primarily MIDI stuff, right?
I use PD, Audacity, and I am learning Ardour. PD rocks but the other 
two still need a few UI improvements to be the Soundforge and Sonar I 
am used too in Winblows land. Also I need to put linux on my iPod so I 
can play flac files...

> Packaging alternative kernels in Extras is a can of worms I don't think
> anyone is in a rush to open. But as far as I know its not yet totally
> out of the question...

I have no problem adding the CCRMA repo to my yum.repos.d directory, as 
I do now with FC4. What is the advantage of including CCRMA in Fedora 
Extras? Just default install inclusion I imagine.

-wade