Natty and RT Kernel (was "Maverick and RT")

[Jeremy Jongepier]

On 09/30/2010 08:37 AM, Alessio Igor Bogani wrote:
> Hi Jeremy,
> 
> 2010/9/30 Jeremy Jongepier <jeremy at autostatic.com>:
> [...]
>> multimedia room with some Ubuntu machines). I've actually never seen a
>> -realtime kernel, what's the difference from -rt? -lowlatency doesn't
> 
> From a technical point of view -rt and -realtime are the same kernel.
> A minor difference is that the -rt kernel offer the "really stable"
> and upstream official release 2.6.31 whereas -realtime offers the last
> official upstream release that is 2.6.33. But there are the same
> kernel (that is PREEMPT_RT). The main difference is the external
> support. In -rt I have tried to offer an usable system as like Ubuntu
> do (so I have worked on compatibility with closed video drivers for
> example like nvidia or fglrx) whereas with -realtime I don't enforce
> it at all.
> 
> In less words: if you need of closed video drivers, external DKMS
> kernel modules, linux-backports-* you should probably start to use
> -lowlatency (when it will be available through Ubuntu repos). Instead
> if you really need of an real-time system you should avoid all above
> or trying to make those working alone.
> 

Thanks for the explanation. Personally I don't care about external
support and I'm very happy with the open source nouveau and radeon
drivers. From a community perspective it's different though and I think
we shouldn't loose that out of sight either. I'd really like to know how
everyone else thinks about that, what is the common ground towards
-rt/-realtime etc.?

>> cut it for me, like I said, I need the tasklet API the -rt kernel
>> provides so I can use rtirq.
> 
> Probably you meant IRQ Threads.
> 

I need the tasklet API the -rt kernel provides so I can use rtirq to
prioritize IRQ threads ;)

>> Concerning support, it would be best if there were kernels for every
>> release simply because it would be a bummer if people would move away
>> from Ubuntu because of this.
> 
> That require a lot of energy. If a lot of people will be available for
> help we could do it.
> 
> Ciao,
> Alessio
> 

I understand and maybe my opinion on this was a bit premature. It maybe
a good thing to think about how many Ubuntu users are actually using the
-rt kernel and if it's really worth the effort in putting a lot of
energy in maintaining these kernels.

Best,

Jeremy