[LAU] difference between realtime-kernel and low-latency-kernel?

[Frank Barknecht]

Hallo,
Matthias Schönborn hat gesagt: // Matthias Schönborn wrote:
> I've just read that there's a difference between a realtime-kernel and the 
> low-latency-kernel provided by ubuntustudio. The text in the german wiki on 
> ubuntuusers.de said, that a realtime-kernel is slightly better than the 
> lowlatencykernel (http://wiki.ubuntuusers.de/Echtzeitkernel) - then why isn't 
> it used in ubuntustudio? Or do I just mix something up?

I think, this wiki and maybe Ubuntustudio as well are using a very
confusing terminology. 

Generally we have two kinds of kernels: The "vanilla" kernel as
downloadable on kernel.org and the same kernel, but patched with Ingo
Molnars RT-patches. The vanilla kernel, if configured properly with
CONFIG_PREEMPT etc., already gives very good performance in the low
latency department, enough for many users, even audio users. I run one
of these. 

If you want more, then you can install a RT-patched kernel, as is
provided in the linux-rt or linux-realtime packages.  I would call the
Ingo-Molnar-patched kernels Realtime-Kernels or Low-Latency-Kernels. 

I would not call the vanilla kernel a "low latency" kernel. It's just
a vanilla kernel configured with CONFIG_PREEMPT, which happens to have
good low latency performance as well. But that alone shouldn't be
taken to give it a different name. It has good network performance,
too, but I still wouldn't call it a "network kernel" and it supports
USB keyboards, but still it's not a "USB keyboard kernel". That's a
bit silly. ;) 

Ciao
-- 
 Frank Barknecht                                     _ ______footils.org__