[Rtai] Isolate tasks in other core

Ignacio Orta Caamaño i42orcai at uco.es
Tue Dec 22 13:18:19 CET 2009

Hello all, I've a problem while trying to isolate a task in another  
core with rtai.

I've Ubuntu Karmic with a 2.6.31 original kernel (not the ubuntu one)  
patched with rtai 3.8-test1 that have been recently launched.

I'm doing a new version of a linux version for execute tasks with rtai  
and using papi with perf counters to make stadistics for the university.

The last version could launch tasks in both cores or in exclusive in  
one of the cores of the computer. When it launch a task with  
isolatecpus in the core that is isolated, it can execute alone in that  
core without scheduler problems for best results.

My problem is that i can't make this with this new version with the  
same code. When I isolate a cpu, the tasks always execute in the core  
that's not have been isolated. For that I use rt_task_init_schmod with  
the mask of cpus_allowed (for example, for cpu0 it uses 0x1 (1 in int,  
001 in binary), for the cpu1 it uses 0x2 (2 in int, 010 in binary),  
the cpu3 0x4 (4 in int, 100 in binary), etc.

The problem that I've is that i cant force to use the cpu of the  
rt_task_init_schmod instruction in the isolated cpu, and I don't know  
if its a problem with the kernel configuration, with rtai, or another  
thing. I hope that someone could help me with that and give me some  
hints for solve that.

Thanks for all!

Ignacio Orta Caamaño - Ingeniero en Informática
Universidad de Córdoba
E-Mail: i42orcai at uco.es

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