Uptime difference between FreeBSD and RTEMS

Gedare Bloom gedare at rtems.org
Wed Apr 1 18:51:03 UTC 2015


On Wed, Apr 1, 2015 at 2:42 PM, Sebastian Huber
<sebastian.huber at embedded-brains.de> wrote:
>
> ----- Joel Sherrill <joel.sherrill at oarcorp.com> schrieb:
>>
>>
>> On 4/1/2015 9:18 AM, Gedare Bloom wrote:
>> > Would you then subtract 1 from uptime when reporting it? Or would
>> > users be expected to know that uptime is off-by-1?
>> I would prefer we subtract one when reporting to the user.
>
> The question is reporting via which API.  We have the RTEMS and POSIX APIs and the FreeBSD kernel APIs.  So the consensus is to report uptimes relative to zero for the RTEMS and POSIX APIs and relative to one second for the FreeBSD kernel APIs?
>
Yes I think so. We don't really want to change the expected behavior
of existing APIs just to comply with FreeBSDs.

>> > On Wed, Apr 1, 2015 at 4:07 AM, Alexander Krutwig
>> > <alexander.krutwig at embedded-brains.de> wrote:
>> >> Hello,
>> >>
>> >> during my work with FreeBSD timecounters, I found out that the FreeBSD
>> >> timecounters start with an uptime value of 1 second. Developers of FreeBSD
>> >> told me that this is due to problems in the ARP code.
>> >> RTEMS uptime is initialized to an uptime value to 0 seconds.
>> >> Are there any problems if the configuration of the RTEMS uptime is also
>> >> initialized to 1 second for synchonization? Else, we would have different
>> >> values for different API functions which is the second option.
>> >>
>> >> Best regards,
>> >> Alexander Krutwig
>> >>
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>> --
>> Joel Sherrill, Ph.D.             Director of Research & Development
>> joel.sherrill at OARcorp.com        On-Line Applications Research
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