[LITMUS^RT] Running LITMUS-RT on ARM64

[Björn Brandenburg]

> On 28. Aug 2017, at 15:39, Andrii Anisov <andrii_anisov at epam.com> wrote:
> 
> Could you please explain why do I see that some tasks execution time do not conform with one what was configured. E.g.:
>    1. PID 1550 with WCET 5ms, in period 20-to-30ms is represented with ~3,5ms execution time
>    2. PID 1554 with WCET 3ms, in period 10-to-20ms is represented with ~5ms execution time
> and so on.

Well, rtspin’s spin loop is not "cycle accurate", so some variation is always possible. However, rtspin usually doesn’t show such large runtime variations (unless you specifically ask for it with -u/-U), so something else appears to be going on here.

Perhaps it is related to virtualized time? Can you reproduce the effect on bare metal (i.e., on native LITMUS^RT without any virtualization layer)?

- Björn