[RTEMS Project] #2348: Timecounter: Add NTP support

[RTEMS trac]

#2348: Timecounter: Add NTP support
-----------------------------+-------------------------
 Reporter:  Sebastian Huber  |       Owner:  (none)
     Type:  enhancement      |      Status:  new
 Priority:  normal           |   Milestone:  Indefinite
Component:  score            |     Version:
 Severity:  normal           |  Resolution:
 Keywords:                   |  Blocked By:
 Blocking:                   |
-----------------------------+-------------------------

Comment (by Chris Johns):

 Replying to [comment:3 Sebastian Huber]:
 > Good timing, I recently updated kern_tc.c to the latest FreeBSD version:

 It does seem so. :)

 > https://git.rtems.org/sebh/rtems.git/log/?h=timecounter-2021
 >
 > I just didn't send the patch set for review yet, since nobody commented
 on the new clock manager directives so far:

 I only suspected something was in the works because of the posts to
 FreeBSD hackers. It would be good to resolve the PTP support.

 > https://lists.rtems.org/pipermail/devel/2021-October/069697.html

 I saw this but I did not look closely. I did not know it was a request for
 a new feature. I will add it to my list so sorry about that.

 > The kern_tc.c is quite close to the original FreeBSD code and the
 Doxygen comment block on top of the file is not an issue.

 Why the special exception here?

 My focus for the leadership group, including you, is to set policies for
 this sort of thing and then having everyone accept and adhere to them. It
 is simpler and more democratic to do this. My concern is having a rule
 that creates an exceptions because it makes things  complicated. I know
 this is a single file but there are other places where more code comes
 across and this is where things become confusing.

 > In this patch set I removed the NTP code block since nobody was
 interested in NTP support in the last 6 years:
 >
 >
 https://git.rtems.org/sebh/rtems.git/commit/?h=timecounter-2021&id=f85259b1edfff1d89c013c97510a9427825ea81b

 It is needed. I have openly discuss this topic ...

 https://lists.rtems.org/pipermail/devel/2021-March/065608.html

 The PTP changes for RTEMS have only just been posted upstream ..

 https://github.com/ptpd/ptpd/pull/85

 Gabriel has done a fantastic job getting my hacks into a suitable state
 they would be pushed upstream.

 > This enabled a performance optimization here:
 >
 >
 https://git.rtems.org/sebh/rtems.git/commit/?h=timecounter-2021&id=04ed8d3c8cf88b7f1e3fb7ad78a91be1fefc396c
 >
 > The performance optimization is important for targets with slow 64-bit
 divisions (which are most RTEMS targets). If you want to add NTP support,
 then we have to restructure the FreeBSD code a bit. This can be integrated
 in FreeBSD. I can do this it just depends on how urgent it is.

 I have nothing to offer here and will happily be guided by you. I am sorry
 I have no time to spend looking at the detail.

 > In a first approach the proposed callback makes sense. If someone using
 lwIP needs NTP support, then we can add kern_ntptime.c to RTEMS.

 The support being added is LibBSD so I am not sure where `kern_ntptime.c`
 is being added. Maybe Gabriel can be comment more on this.

--
Ticket URL: <http://devel.rtems.org/ticket/2348#comment:4>
RTEMS Project <http://www.rtems.org/>
RTEMS Project