[LAU] Realtime Kernel

[Florian Schmidt]

On Tuesday 18 March 2008, Arnold Krille wrote:
> Am Dienstag, 18. März 2008 schrieb Fons Adriaensen:
> > An -rt kernel will be more robust in those cases, and also
> > gives you the tools to optimize your system by assigning
> > interrupt handling priorities. The result is that you can
> > have lower latencies.
>
> Unfortunately this comes at a price:
> During development it is way easier to lock your system when you use an rt
> kernel. Because the amoc-running process with realtime-priority gets all
> the processing time it wants, it can be _very_ hard to get the system to
> react to keyboard/mouse or network-ssh to get it back under control...
> Of course this isn't really an issue for the mere user.

You don't need an -rt kernel to hardlock your system with a runaway SCHED_FIFO 
or SCHED_RR process. It works just as well on a vanilla kernel. To avoid this 
the only thing you can do is to either 

a] run a watchdog app (mine is a bit broken atm, so i cannot recommend it)

b] do not run SCHED_FIFO or SCHED_RR processes.

Using an -rt kernel has nothing to do with it.

Flo


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