[Xenomai-help] How do I increase CPU time limit.

[Xenomai-help] How do I increase CPU time limit.

[Chris Stone]

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I have a thread which uses a lot of CPU and it is receiving a SIGXCPU: Cpu time limit exceeded. Does this message really mean I have exceeded some CPU time limit? If so, how do I increase or disable the CPU time limit? The code that I am running has been working for quite some time under regular Linux and I have just ported it to Xenomai, so I doubt there are any infinite loops in it.

Chris Stone
Senior Software Engineer
Optelian
1 Brewer Hunt Way
Ottawa, Ontario K2K 2B5

Phone: 613-287-2000 x2106

www.optelian.com<http://www.optelian.com>


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Re: [Xenomai-help] How do I increase CPU time limit.

[Mustafa ÇAMURLI]

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make sure that "cpu time" is unlimited. You can check and change it with
"ulimit" util. Use  "limit -a" to list all about limitations.


On Tue, Mar 20, 2012 at 4:09 PM, Chris Stone <chris.stone@domain.hid>wrote:

>  I have a thread which uses a lot of CPU and it is receiving a SIGXCPU:
> Cpu time limit exceeded. Does this message really mean I have exceeded some
> CPU time limit? If so, how do I increase or disable the CPU time limit? The
> code that I am running has been working for quite some time under regular
> Linux and I have just ported it to Xenomai, so I doubt there are any
> infinite loops in it.****
>
> ** **
>
> *Chris Stone*
>
> Senior Software Engineer****
>
> Optelian****
>
> 1 Brewer Hunt Way****
>
> Ottawa, Ontario K2K 2B5****
>
> ** **
>
> Phone: 613-287-2000 x2106****
>
> ** **
>
> *www.optelian.com*****
>
> ** **
>
> _______________________________________________
> Xenomai-help mailing list
> Xenomai-help@domain.hid
> https://mail.gna.org/listinfo/xenomai-help
>
>


-- 
MC

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Re: [Xenomai-help] How do I increase CPU time limit.

[Philippe Gerum]

On 03/20/2012 03:09 PM, Chris Stone wrote:
> I have a thread which uses a lot of CPU and it is receiving a SIGXCPU:
> Cpu time limit exceeded. Does this message really mean I have exceeded
> some CPU time limit? If so, how do I increase or disable the CPU time
> limit? The code that I am running has been working for quite some time
> under regular Linux and I have just ported it to Xenomai, so I doubt
> there are any infinite loops in it.

This could be the runaway thread detector triggering, after 4s of 
uninterrupted runtime (which is huge, is this intended?). This is a 
debug mechanism Xenomai implements to recover from a runaway thread 
chewing CPU in primary mode, without having to resort to the reset button.
You can either extend the grace period above the default 4s, using 
CONFIG_XENO_OPT_WATCHDOG_TIMEOUT, or disable the watchdog entirely by 
switching off CONFIG_XENO_OPT_WATCHDOG. This said, 4s is really long 
already, so the regular kernel might not cope with even more starvation 
from normal interrupts.

Other explanation would be not time-related. If 
CONFIG_XENO_OPT_DEBUG_SYNCH_RELAX is enabled, any attempt to switch to 
secondary mode while holding a real-time (Xenomai created) mutex in the 
code would trigger such signal, as a warning to point out a priority 
inversion.

>
> *Chris Stone*
>
> Senior Software Engineer
>
> Optelian
>
> 1 Brewer Hunt Way
>
> Ottawa, Ontario K2K 2B5
>
> Phone: 613-287-2000 x2106
>
> _www.optelian.com <http://www.optelian.com>_
>
>
>
> _______________________________________________
> Xenomai-help mailing list
> Xenomai-help@domain.hid
> https://mail.gna.org/listinfo/xenomai-help


-- 
Philippe.

Re: [Xenomai-help] How do I increase CPU time limit.

[Gilles Chanteperdrix]

On 03/20/2012 03:43 PM, Philippe Gerum wrote:
> On 03/20/2012 03:09 PM, Chris Stone wrote:
>> I have a thread which uses a lot of CPU and it is receiving a SIGXCPU:
>> Cpu time limit exceeded. Does this message really mean I have exceeded
>> some CPU time limit? If so, how do I increase or disable the CPU time
>> limit? The code that I am running has been working for quite some time
>> under regular Linux and I have just ported it to Xenomai, so I doubt
>> there are any infinite loops in it.
> 
> This could be the runaway thread detector triggering, after 4s of 
> uninterrupted runtime (which is huge, is this intended?). This is a 
> debug mechanism Xenomai implements to recover from a runaway thread 
> chewing CPU in primary mode, without having to resort to the reset button.
> You can either extend the grace period above the default 4s, using 
> CONFIG_XENO_OPT_WATCHDOG_TIMEOUT, or disable the watchdog entirely by 
> switching off CONFIG_XENO_OPT_WATCHDOG. This said, 4s is really long 
> already, so the regular kernel might not cope with even more starvation 
> from normal interrupts.
> 
> Other explanation would be not time-related. If 
> CONFIG_XENO_OPT_DEBUG_SYNCH_RELAX is enabled, any attempt to switch to 
> secondary mode while holding a real-time (Xenomai created) mutex in the 
> code would trigger such signal, as a warning to point out a priority 
> inversion.

You may find an example of how to install a SIGXCPU handler and decode
signals sent by xenomai in examples/native/sigdebug.c

-- 
                                                                Gilles.