Re: [Xenomai-core] Getting the clock model right

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

Jan Kiszka wrote:
> Gilles Chanteperdrix wrote:
> 
>>Jan Kiszka wrote:
>>
>>>Hi,
>>>
>>>recent announcement of some new TSC synchronisation feature in RTAI made
>>>me stick my nose into this and think about the whole issue of clock
>>>synchronisation again. Well, let's not talk about RTAI details here, but
>>>they got one thing right: as long as we cannot handle unsynch'ed TSC on
>>>SMP, we need some detection and alarming as the bare minimum.
>>>
>>>Why can't we handle such cases yet? First, there seems to be still some
>>>bugs hidden in the core (one example: xntimer_start_aperiodic() uses the
>>>local time stamp to start a remote timer).
>>
>>Reading the code, there seem to be only two places where the local tsc
>>is used to set a remote timer, it is xntimer_start_aperiodic, and
>>xntimer_move_aperiodic, which is used by xntimer_migrate. So we are left
>>with only one bug: starting a timer on the remote CPU, this could easily
>>be implemented with a queue which would be handled by the timer IPI.
>>
> 
> 
> As I said: fixable based on thorough review - but only a minor part of
> the problem.

I fail to see the remaining part of the problem.

-- 
                                                 Gilles Chanteperdrix