Rodrigo Rosenfeld Rosas wrote:
> Em Segunda 13 Março 2006 08:48, você escreveu:
>> ...
>>> Do you mean that rtdm_clock_read will always read a multiple of tickval
>>> value? If so, I think it would be good to make it clear on its
>>> documentation. "Get system time" isn't enough for getting this
>>> information, IMHO.
>> Please have a look at the two sentences of documentation I added to SVN
>> (didn't make it into the release).
> I did.
>> I gave your scenario a try, and I was able to verify that
>> rtdm_task_busy_sleep works correctly under both timer modes.
> I cannot understand yet why it doesn't occur here, but I'll investigate if I
> have the time to.

I counted the loops rtdm_task_busy_sleep took, and they were quite
similar (IRQ noise aside).

>> Indeed, the
>> behaviour of rtdm_clock_read may have been confusing due to lacking
>> information, but it was also correct.
> I liked the note, but I would include another one:
> "When in periodic mode, the time resolution is limited to the tick set to the
> system timer" or something like. Maybe:
> "[If using periodic mode, note that ]The time resolution is limited by the
> system timer tick". Well my English is not that good, so I think you could
> give a better description, but I really need this note is very useful.

"Resolution" is the accurate term, indeed. To include what I think is
the core of your suggestions:

"The resolution of the this service depends on the system timer. In
particular, if the system timer is running in periodic mode, the return
value will be limited to multiples of the timer tick period."

Actually, the resolution based on TSC is also limited - when your CPU
has less then 1 GHz. ;)


Attachment: signature.asc
Description: OpenPGP digital signature

Xenomai-core mailing list

Reply via email to