This would need only a trivial change to documentation, which then
doesn't need a full RST build/check I would think.
On 26/11/2025 19:04, Tim Hardisty wrote:
Think my message passed yours in the ether...yes; that's what I'm
suggesting :-)
On 26/11/2025 19:02, Alan C. Assis wrote:
I think what we are calling "Strict Priority" is defined by POSIX as
SCHED_FIFO.
SCHED_FIFO: The thread runs until it blocks itself or it is preempted
by a
higher priority thread. (This is what you want).
SCHED_RR: The thread runs until the above happens *OR* its time slice
(200ms) expires.
So, we could create a choice in the menuconfig with these three options:
SCHED_FIFO
SCHED_RR
SCHED_SPORADIC
If SCHED_FIFO is selected, the RR_INTERVAL is set to 0. If SCHED_RR is
selected the option to set RR_INTERVAL value will show up.
What do you think?
BR,
Alan
On Wed, Nov 26, 2025 at 3:40 PM Alan C. Assis <[email protected]> wrote:
Do you suggest moving from RST to Markdown?
I think SCHED_PRIORITY is not a standard definition, at least I didn't
find it in POSIX.
You can propose using RR slice equal 0 by default, but I don't know the
side effects (it could be considered a breaking change, because some
user
applications could stop working or behave strangely).
BR,
Alan
On Wed, Nov 26, 2025 at 3:27 PM Tim Hardisty <[email protected]>
wrote:
I don't mind doing documentation - but it does take a lot more effort
since RST doesn't have very good previewers that I have found: it is
difficult to know if will it render correctly on the website unless
you
do the whole RST build stuff.
Quicker - if agreeable as a short term fix - would be to add a Kconfig
option to specifically choose the scheduling option, with an
appropriate
CONFIG_RR_INTERVAL setting of 0 for SCHED_PRIORITY or 200ms for
SCHED_RR? That would mean no code changes as such?
Something like that anyway. If it fixes my issue, I can play with this
and do a PR
On 26/11/2025 18:16, Alan C. Assis wrote:
Guess what? We are still missing a proper Documentation! :-)
BR,
Alan
On Wed, Nov 26, 2025 at 3:11 PM Tim Hardisty
<[email protected]>
wrote:
So do we agree the documentation is at best misleading? And, to me,
simply wrong?
On 26/11/2025 18:07, Alan C. Assis wrote:
Exactly!
You can refer to sched/sched/sched_timerexpiration.c line 207
On Wed, Nov 26, 2025 at 3:00 PM Tim Hardisty
<[email protected]
wrote:
That's what I inferred (yet to try it) - so is the documentation
misleading since the default CONFIG_RR_INTERVAL=200 forces RR
scheduling
rather than the stated "strict priority scheduling"?
On 26/11/2025 17:54, Alan C. Assis wrote:
CONFIG_RR_INTERVAL=0
On Wed, Nov 26, 2025 at 2:22 PM Tim Hardisty <
[email protected]>
wrote:
Apologies if this isn't really a NuttX question...
Documentation says "By default, NuttX performs strict priority
scheduling".
Default CONFIG_RR_INTERVAL is 200ms.
I have multiple threads, but have not set any scheduling
parameters,
but
it seems threads are being scheduled every 200ms rather on a
priority
basis.
What *should* I be doing, please, to get all my threads
scheduled
by
priority?
Thanks,
TimH
PS - yes I have thrown myself in the deep end without a life
jacket
with
my project. And I'm no doubt up ****-creek without a paddle.
But I
am
always learning!
