[Rtai] running an infinite loop RTAI task

[Alex Ivanov]

Hi Bernhard,

I have a feeling we'll need to stop local timer interrupts to get this
thing going. I am not sure what these interrupts are, but on RTLinux the
LOC counter in /proc/interrupts is not changing for the isolated cpus. In
RTAI it does regardless of the isolation method. Does anyone know what
these local timer interrupts are and if there is a way to stop them?

Thanks, Alex

On Fri, 26 Sep 2008, Bernhard Pfund wrote:

> Alex Ivanov wrote:
> > 
>  > I have tried Bernard's script and it changes nothing for me, still the
> > same problem with some programs just getting stuck and the whole OS
> > eventually getting in a locked up state, nonresponsive. I do get an error
> > message from the script about cgroup filesystem non-existent, not sure
> > what to make of it.
> > 
> > Alex
> > 
> 
> Hi Alex,
> 
> forgot to mention, and this is also something for the howto, you have to
> enable cgroups in the kernel (CONFIG_CGROUPS=y). I'll add that to
> README.ISOLCPUS.
> 
> Have you tried off/on-lining the cpu manually? You should see no more
> IRQs handled on the cpu(s) in question. For me it looks like that:
> 
> :~$ cat /proc/interrupts
>            CPU0       CPU1       CPU2       CPU3
>   0:        187          0          0          0   IO-APIC-edge      timer
>   1:        519          0          0          0   IO-APIC-edge      i8042
>   7:          1          0          0          0   IO-APIC-edge
>   8:          3          0          0          0   IO-APIC-edge      rtc
>   9:          0          0          0          0   IO-APIC-fasteoi   acpi
>  14:         48          0          0          0   IO-APIC-edge
> pata_amd
>  15:          0          0          0          0   IO-APIC-edge
> pata_amd
>  19:     124173          0          0          0   IO-APIC-fasteoi   eth0
>  21:         63          0          0          0   IO-APIC-fasteoi
> ohci_hcd:usb2
>  22:          3          0          0          0   IO-APIC-fasteoi
> ehci_hcd:usb1
>  23:      54407          0          0          0   IO-APIC-fasteoi   ahci
> NMI:          0          0          0          0   Non-maskable interrupts
> LOC:     673982     545805     485702     536756   Local timer interrupts
> RES:      63293      65539      63465      38076   Rescheduling interrupts
> CAL:         42        127        122         89   function call interrupts
> TLB:        209        169        411        396   TLB shootdowns
> TRM:          0          0          0          0   Thermal event interrupts
> SPU:          0          0          0          0   Spurious interrupts
> ERR:          1
> MIS:          0
> 
> 
> Bernhard
>