Jan Kiszka wrote:
> Jan Kiszka wrote:
>> Gilles Chanteperdrix wrote:
>>> Jan Kiszka wrote:
>>>> xenomai-git-requ...@gna.org wrote:
>>>>> diff --git a/include/asm-generic/bits/current.h 
>>>>> b/include/asm-generic/bits/current.h
>>>>> index f0e569c..b9ac680 100644
>>>>> --- a/include/asm-generic/bits/current.h
>>>>> +++ b/include/asm-generic/bits/current.h
>>>> ...
>>>>
>>>>> @@ -33,25 +33,16 @@ static inline xnhandle_t xeno_get_current(void)
>>>>>  {
>>>>>   void *val = pthread_getspecific(xeno_current_key);
>>>>>  
>>>>> - if (!val)
>>>>> -         return XN_NO_HANDLE;
>>>>> -
>>>>> - return (xnhandle_t)val;
>>>>> + return (xnhandle_t)val ?: xeno_slow_get_current();
>>>>>  }
>>>> So when used with normal Linux threads, this will always trigger the
>>>> syscall of xeno_slow_get_current()?
>>>>
>>>>> diff --git a/src/rtdk/assert_context.c b/src/rtdk/assert_context.c
>>>>> index bad19f3..f67bcd8 100644
>>>>> --- a/src/rtdk/assert_context.c
>>>>> +++ b/src/rtdk/assert_context.c
>>>>> @@ -30,12 +30,9 @@ void assert_nrt(void)
>>>>>   xnthread_info_t info;
>>>>>   int err;
>>>>>  
>>>>> - if (xeno_get_current() != XN_NO_HANDLE)
>>>>> -         return;
>>>>> + if (unlikely(xeno_get_current() != XN_NO_HANDLE &&
>>>>> +              !(xeno_get_current_mode() & XNRELAX))) {
>>>> Then please provide a different API for assert_nrt as this makes the
>>>> service too heavy for common use.
>>> It is a non real-time thread. Its performances are not critical. A
>>> non-blocking syscall is not that heavy. Especially compared to the
>>> execution time of malloc. Ok, will not argue on this any more, as
>>> obviously our opinions differ in that area.
>> Sorry, disagree. We are using it in mixed applications where both RT
>> latency as well as non-RT throughput matters. The assert_nrt fast was
>> designed to remain lightweight for both non-Xenomai threads as well as
>> migrated threads.
>>
>>> The point is that NULL (XN_NO_HANDLE) means at the same time a freed
>>> mode and a mode after the TSD cleanup was run. So, emitting a syscall in
>>> that case is the simplest thing we can do. And no, I did not find it
>>> expensive. But in fact, using an additional syscall, assert_nrt could be
>>> implemented as a simple dummy syscall which returns 0 and asks the
>>> caller to be put in primary mode (and it would be even lighter). So, I
>>> guess if you did not implemented that way, it means that you already
>>> wanted to avoid the syscall.
>> Can't follow on this yet.
> 
> ...specifically as an unset current key is a bug for a Xenomai thread.
> Every skin library is supposed to set it, so there should be no need for
> falling back to a syscall for them, and there is no point in trying it
> for non-Xenomai threads.
> 
> So why this fallback? Does it simplify something else that I miss ATM?

After the TSD cleanup is run, the TSD are set to NULL. Actually, I
assumed that when doing this change. I need to check.

> 
> Jan
> 


-- 
                                            Gilles.

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