Re: resend: KERNEL BUG: nice level should not affect SCHED_RR timeslice

[Chris Friesen]

Con Kolivas wrote:

> Indeed we do change timeslice with nice on rt_tasks in mainline at the moment. 
> Truth is most rt programming couldn't care less about timeslices, but your 
> point about it deviating from the standard is valid. RSDL does not change 
> timeslice with nice on SCHED_RR tasks so it's sort of getting addressed by 
> proxy.

Unfortunately we have some vendor-supplied software that does care about 
timeslices.  It's a crazy thing with multiple SCHED_RR kernel threads 
that don't really self-manage very well.  They're spawned by a 
SCHED_OTHER task and inherit its nice level.

We modified the startup for the spawning task to run it at a lower nice 
level and were fairly surprised when the latency of message handling 
went way up.

Chris
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