Uptime difference between FreeBSD and RTEMS

Sebastian Huber sebastian.huber at embedded-brains.de
Thu Apr 2 06:58:32 UTC 2015


On 02/04/15 03:22, Chris Johns wrote:
> On 1/04/2015 7:07 pm, Alexander Krutwig wrote:
>> 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.
>>
> Are saying there are requirements around for systems to have networking
> up and running with the first second after RTEMS starting ? I am
> impressed you can boot, start the BSP timer running, files system up and
> working (flash?), initialised the network stack and have a valid link
> all within one 1 second.
>
> How long does a recent GigE PHY take to negotiate a link with a switch ?

See also:

https://lists.freebsd.org/pipermail/freebsd-hackers/2015-April/047504.html

https://lists.freebsd.org/pipermail/freebsd-hackers/2015-April/047510.html

The FreeBSD network stack is quite complex and I am not able to judge if 
a change in this area is correct or not.

-- 
Sebastian Huber, embedded brains GmbH

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