Partitioned Scheduling

Daniel Krefft daniel.krefft at
Mon Sep 5 12:49:11 CEST 2016


if I understand it right, there is only one scheduler in the kernel
realizing one distinct scheduling strategy (e.g. fixed prio). However,
given a multi-core system, several (all) cores are using *this* strategy
in an independent core-local style. I'm right?

So, the questions are:

- How can I enhance this approach for several scheduling schemes (not
only one)?

- Where does the mapping between core and scheduling scheme happen?
(e.g. compile-time/run-time)

- Which files do I need to change?

Maybe you can help me to get the big picture (flow chart) of scheduling
in Fiasco.OC because it is vital for the next steps and our research.

Best regards,

Daniel Krefft MSc.
Wissenschaftlicher Mitarbeiter

Technische Universitaet Muenchen
Fakultaet fuer Informatik
Lehrstuhl fuer Betriebssysteme

Arcisstrasse 21
80333 Muenchen

Tel. +49 89 289 18791

daniel.krefft at

On 02.09.2016 23:05, Adam Lackorzynski wrote:
> On Fri Sep 02, 2016 at 20:03:01 +0000, Edinger, Stefan wrote:
>> How does Fiasco.OC manage its Cores ? 
>> Is it possible to execute more than one SchedContext on a multi-core CPU?
> Each core runs its own scheduler and the schedulers are independent of
> each other. Thus they run in parallel and process Schedcontexts on their
> own.
> Adam
>> -----Ursprüngliche Nachricht-----
>> Von: Adam Lackorzynski [mailto:adam at] 
>> Gesendet: Montag, 29. August 2016 23:03
>> An: Edinger, Stefan
>> Cc: l4-hackers at
>> Betreff: Re: Partitioned Scheduling
>> Hi,
>> On Sun Aug 28, 2016 at 18:17:24 +0000, Edinger, Stefan wrote:
>>> is it possible to have partitioned scheduling in the way that one can 
>>> use different schedulers for different cpu-cores?
>> No, there's just one scheduler in the kernel, for all cores.
>> However, given that scheduling is core-local only, cores could principally also have different schedulers.
>>> And if yes, can I do the mapping from scheduler to core on runtime or 
>>> is it done at compile time?
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