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Date: Tue, 10 Apr 2012 17:55:41 +0200
From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
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Subject: Re: [Xenomai-core] preemptive doesn't work
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To: Roberto Bielli <roberto.bielli@domain.hid>
Cc: xenomai@xenomai.org

On 04/10/2012 02:58 PM, Roberto Bielli wrote:
> In the xenomai example the task periodic is 2ms not 200us. ( 
> rt_task_sleep( 2ms 000us 000ns ) );

sorry, I misred.

> And the 10ms is because the default system time period of the timer 
> without xenomai is ~10ms.
> So a process that execute in linux base can be re-scheduled only when 
> the timer generate an interrupt , the task makes I/O, or sleeps.

That is only if you do not use CONFIG_HIGH_RES_TIMERS, in which case you
are not in the same configuration as xenomai, and the test does not mean
anything.

> 
> 
> 
> Il 10/04/2012 14:36, Gilles Chanteperdrix ha scritto:
>> On 04/10/2012 02:33 PM, Roberto Bielli wrote:
>>> Il 10/04/2012 13:49, Gilles Chanteperdrix ha scritto:
>>>> On 04/10/2012 12:39 PM, Roberto Bielli wrote:
>>>>> Hi Gilles,
>>>>>
>>>>> i tried your code but th behavior is the same.
>>>>>
>>>>> Then i tried a linux base app and works correctly.
>>>> In the exact same conditions? With the crunching task running with
>>>> SCHED_FIFO, priority 1, and the periodic task running with SCHED_FIFO,
>>>> priority 99, and the linux real-time throttling disabled?
>>>>
>>> Yes, and i see that every LATCH ( about ~10ms ) period the task with
>>> higher priority is wakeup.
>> In the example you sent the periodic task was running with a 200us
>> period, not 10ms.
>>
> 
> 


-- 
                                                                Gilles.