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

["Randy Brukardt" <randy@rrsoftware.com>]

"AdaMagica" <christ-usch.grein@t-online.de> wrote in message 
news:1d798609-8b73-4bc6-b74f-e435e8af8fedn@googlegroups.com...
> Dmitry A. Kazakov schrieb am Samstag, 12. Juni 2021 um 17:57:39 UTC+2:
>> Because under Windows the default priority is in the time sharing class.
>> As the name suggests such threads are preempted when the their quant
>> expires. AFAIK, even a lower priority thread can preempt a higher
>> priority one if both are time sharing. Time sharing priority only
>> influences the duration of the quant and the chances to gain the 
>> processor.
>
> Hm OK. Is this compatible with the Ada RM?

Not really, at least in an Annex D sense. (The core doesn't require much, in 
part so Ada will work on a wide variety of targets.) Pretty much everyone 
has agreed to ignore the impossibility of implementing Annex D on Windows --  
remember that there is an "impossible or impractical" exception in 1.1.3 
which certainly applies in this case. Indeed, I suspect that it is 
impossible to implement all of Annex D on any target other than a bare 
machine. (One example is that there is no known implementation of EDF 
scheduling even though Annex D seems to require it to be implemented.)

                               Randy.