[ag-automation] hard rt ????

[David Kline]

carsten,

i downloaded cyclictest.c, header, and makefile from the git website and 
complied it; however
when i run the application as described below it freezes the machine.

ideas?

vielen dank im voraus,
/david

Carsten Emde wrote:
> David,
>
>> I have built the vanilla linux kernel 2.6.19 with the realtime patch 
>> (rt15)
>> and was curious if it is now considered hard realtime?
> We really do not differentiate between hard and soft realtime. 
> Realtime compliance is like pregnancy - yes or not. There is no such 
> thing as a bit pregnant nor is there a bit realtime. "Soft realtime" 
> is important in the domain of marketing not engineering.
>
> Yes, a vanilla Linux kernel patched with the realtime-preempt patch is 
> considered "to have the potential to provide realtime performance". 
> However, your system is not necessarily a realtime system. Your BIOS 
> may have installed System Management Interrupts that will paralyze 
> your system from time to time, some drivers may busy wait or some 
> other mechanisms may counteract with the realtime-preempt patches.
>
> This is why the realtime-preempt patches provide a large number of 
> test tools. As an initial test, we would propose that you run 
> cyclictest, e.g.
>
> # cyclictest -t 3 -n -p 99
>
> More details are given here:
> http://www.osadl.org/Realtime-Preempt-Kernel.kernel-rt.0.html
>
>
> Regards,
>
> Carsten Emde.


-- 

+-------------------------------------------------+
David M. Kline                   dkline at aps.anl.gov
Beamline Controls and Data Acquisition (BCDA)
Argonne National Laboratory, Advanced Photon Source
Argonne IL, 60439                      630.252.8639
   ---------------------------------------------
                   Beamlines R Us
+-------------------------------------------------+