The different realtime kernels

[Ralf Mardorf]

On Thu, 2010-09-30 at 16:38 +0200, Ralf Mardorf wrote:
> On Thu, 2010-09-30 at 07:35 -0400, Ronan Jouchet wrote:
> > Hello everybody,
> > 
> > Many are confused about the various realtime kernels, so here is a 
> > reminder of the situation as of Sept. 2010 (but _please_ see 
> > https://help.ubuntu.com/community/UbuntuStudio/RealTimeKernel , which is 
> > more detailed and continuously updated).
> > 
> > ***Summary***
> > vanilla = unpatched kernel straight from kernel.org
> > generic = vanilla + ubuntu sauce (it's the default ubuntu kernel)
> > 
> > The *soft realtime kernels, prepared by changing build-time parameters*
> >      preempt = generic + mild configuration to reduce latency
> >      lowlatency = generic + aggressive configuration to reduce latency
> > 
> > The *hard realtime kernels, prepared by applying a big patch* from Ingo 
> > Molnar to the kernel source before building:
> >      realtime = vanilla + patch (hard to maintain and stabilize because 
> > merging 2 pieces of code is never easy)
> >      rt = generic + patch (even harder to maintain and stabilize because 
> > merging 3 pieces of code is harder than 2)
> > 
> > ***Availability***
> > - for Maverick, generic will be the only kernel in the archives, thus 
> > the default kernel for ubuntu and ubuntustudio, but Alessio has been 
> > maintaining a PPA providing lowlatency and realtime
> > - for Natty or later: work is being done to include lowlatency in the 
> > official archives and make it the default ubuntustudio kernel
> > 
> > I hope this clears some doubts. By the way, this confusion is only going 
> > to get more intense at release time (less informed / technical users). 
> > Could we include some kind of note informing users about this? Why not a 
> > "RealTime kernel help" item in the Audio Production menu, redirecting to 
> > the wiki page?
> > 
> > Good day,
> > 
> > -- Ronan Jouchet
> 
> For what do multimedia users (producers, but consumers) need more, but
> vanilla + rt-patch? Does somebody run a multi-user data server on the
> same machine, as he is using in his audio or audio-video studio? This
> would be nonsense.
> 
> 2 cents,
> Ralf

PS: Ok, on 32-bit architecture some might need support for large RAM in
addition, this might be an additional patch, hat's not needed on 64-bit
architecture.