Re: non-preemptive tasking on GNAT 2020 Windows 10 multicore AMD

[Dan Winslow <dandwinslow@gmail.com>]

On Saturday, June 12, 2021 at 1:02:58 PM UTC-5, Niklas Holsti wrote:
> On 2021-06-12 19:03, AdaMagica wrote: 
> > There is another importatn point. X and Y are global, and a task may 
> > update globals only at dispatching points.
> Updates to globals can be delayed, yes. But where in the RM does it say 
> that a task cannot delay updates to non-volatile globals past 
> dispatching points? 
> 
> I haven't found any connection between dispatching points and updates to 
> globals in RM Annex D, where dispatching points are defined.
> > So taks One could infact consider Y constant within the loop.
> Yes.

Yes, that was my thought too, but I'm no expert. These tasks have no dispatches at all, that's the point. I expected whichever one started first to run to completion, then the other while main was pending exit (or looping, as I set up later). They were both on the same CPU, non-preemptive was set, yet they clearly task switched.