Kernels for low latency/real time environments

Alessio Igor Bogani abogani at
Fri Mar 12 12:42:39 UTC 2010

Hi All,

For those who are interested I have placed two new kernels
(-lowlatency and -realtime) into my PPA:

The -lowlatency kernel contains a more aggressive configuration to
reduce latency than the -preempt one. But like -preempt it doesn't
contain any code changes (so both start from the same -generic source

The -realtime kernel contains the upstream version of PREEMPT_RT
patchset applied to a vanilla Linux kernel. The Ubuntu Archive already
provides the linux-rt package but it uses the Karmic source tree as
base for PREEMPT_RT patchset.

The PPA also contains meta-packages so that after you have added PPA
into your Ubuntu system a simple "sudo apt-get install linux-realtime"
or "sudo apt-get install linux-lowlatency" will install what you need.
There is also a recent copy of rt-tests for evaluation and comparison
of all kernels and to better identify which meets your needs.

I suggest following these simple rules:

*) if you don't need a low latency system use -generic kernel
*) If you need a low latency system please use -preempt kernel as a
first choice (this reduces latency but doesn't sacrifice power saving
features) from the Ubuntu archives directly from Ubuntu Kernel Team
*) If you have an i386 system or -preempt isn't enough for your needs
you should try the -lowlatency kernel present in my above-mentioned
*) If -lowlatency also isn't enough you should try the -realtime
kernel (like -lowlatency it is available through my PPA)

Feel free to get in touch with me if you find these useful.



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