Re: [Xenomai-core] [Combo-PATCH] Shared interrupts (final)

[Wolfgang Grandegger <wg@domain.hid>]

Jan Kiszka wrote:
> Wolfgang Grandegger wrote:
>> Hello,
>>
>> Dmitry Adamushko wrote:
>>> Hi,
>>>
>>> this is the final set of patches against the SVN trunk of 2006-02-03.
>>>
>>> It addresses mostly remarks concerning naming (XN_ISR_ISA ->
>>> XN_ISR_EDGE), a few cleanups and updated comments.
>>>
>>> Functionally, the support for shared interrupts (a few flags) to the
> 
> Not directly your fault: the increasing number of return flags for IRQ
> handlers makes me worry that they are used correctly. I can figure out
> what they mean (not yet that clearly from the docs), but does someone
> else understand all this:
> 
> - RT_INTR_HANDLED
> - RT_INTR_CHAINED
> - RT_INTR_ENABLE
> - RT_INTR_NOINT
> 
> or
> 
> - RTDM_IRQ_PROPAGATE
> - RTDM_IRQ_ENABLE
> - RTDM_IRQ_NOINT
> 
> Third-party comments / suggestions welcome as well. Maybe I'm too
> pessimistic.
> 
>>> rtdm (Jan's patch) and native skin.
>>> In the later case, rt_intr_create() now contains the 6-th argument,
>>> namely "int mode".
>>>
>>> Now I'm waiting for the test results from Jan (the previous patch-set
>>> remains to be suitable for testing too in case you are using it
>>> already). Upon success, the new code is ready for merging.
> 
> Trying to manage the priority list of someone else is tricky - I hope we
> can see something soon, but I cannot promise anything.
> 
>>> the patches have to be applied as follows :
>>> - shirq-base
>>> - shirq-v8
>>> - shirq-proc
>>> - shirq-edge
>>> - shirq-ext
>>>
>>> Happy testing ! :)
>> My concern is code size. I see that the patches add substantial amount
>> of code to the ISR. What about make this feature configurable?
>>
> 
> I would vote for the (already scheduled?) extension to register an
> optimised IRQ trampoline in case there is actually no sharing taking
> place. This would also make the "if (irq == XNARCH_TIMER_IRQ)" path
> obsolete.

I still prefer configuration options as they also allow to reduce the 
overall code size (less cache refills and TLB misses). And shared 
interrupts are for x86 only (approximately), I think. Unfortunately, I 
don't have the time to follow all the details of the rapid Xenomai 
development and can't therefore judge what is really necessary.

Wolfgang.

> Jan
>