Re: [Adeos-main] RT ISR re-entrance

[Jan Kiszka <jan.kiszka@domain.hid>]

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张晶 wrote:
> hi,
> 
> Thank you for your reply!
> 
> 2007/8/27, Jan Kiszka <jan.kiszka@domain.hid>:
>> ?? wrote:
>>> hi all,
>>>
>>> In SMP system, an edge triggerred interrupt may be dispatched to
>> multiple
>>> cpus, so the RT ISR of this interrupt may be involved on multiple cpus
>> at
>>> the same time. The question comes: is RT ISR need to be reentrant as
>>> designed or do I miss something?
>> Good question. I would say: yes, it's the I-pipe user's job to take care
>> of re-entrance safety.
>>
>> Vanilla Linux prevents this via the IRQ_INPROGRESS flag. Xenomai 2.4 and
>> since 2.3.2 achieves re-entrance protection for the registered driver
>> handler by holding the IRQ-related spinlock while calling into that
>> handler.
> 
> 
> AFAIK, Xenomai 2.3.3 simply uses the IRQ dispatcher of i-pipe and do not
> supply its own dispatcher.

The Xenomai nucleus does dispatch - to the registered handler(s).

> 
> Still, this isn't something the user should build his system
>> upon. It is rather recommended for determinism and efficiency reasons to
>> assign RT IRQs to a specific CPU.
> 
> 
> Good suggestion！Thanks again!
> 
> HTH,
>> Jan
>>
>>
>>

Jan


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