Re: [Xen-devel] RTDS with extra time issue

[Andrii Anisov <andrii_anisov@xxxxxxxx>]

Dario,


On 12.02.18 12:20, Andrii Anisov wrote:
> Actually as per Meng's explanation and calculations the problem was on 
> my side - wrong DomR task/VCPU parameters.
> I was running the system with dummy loads and values received from 
> CARTS and all seems to be ok (no deadline misses occured).
Well, what I expressed as dummy loads was all domains are generic armv8 
kernels with minimal fs'es running `dd if=/dev/zero of=/dev/null`, 
except DomR. In this case no DL misses occurred with parameters given by 
CARTS.
Now I have real driver domain, Android with GPU sharing. Loads are like 
youtube playback in DomA, dd from mmc through ssh in DomD. And I see 
unexpected DL misses for the same RT configurations.
Well this provides some ground for another my concern about XEN 
scheduling approach. My doubt is that scheduling is done within softirq, 
so all time spent with pcpu for exception itself and possible timer 
actions is accounted for the vcpu which context was interrupted. This 
seems to be not really fair and might be disruptive for RT scheduling.
--

*Andrii Anisov*



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel