Re: [RFC][PATCH 02/22] sched: add extended scheduling interface

[Tommaso Cucinotta]

Il 10/11/2010 23:17, Raistlin ha scritto:
> > I would suggest we add at least one more field so we can implement the
> > stochastic model from UNC, sched_runtime_dev or sched_runtime_var or
> > somesuch.
> Do we need some further mechanism to grant its
> extendability?
> Padding?
> Versioning?
> void *data field?
> Whatever?
This is a key point. Let me copy text from a slide of my LPC main-conf talk:

Warning: features & parameters may easily grow
- Addition of parameters, such as
    - deadline
    - desired vs guaranteed runtime (for adaptive reservations & 
controlled overcommitment)
- Set of flags for controlling variations on behavior
    - work conserving vs non-conserving reservations
    - what happens at fork() time
    - what happens on tasks death (automatic reclamation)
    - notifications from kernel (e.g., runtime exhaustion)
- Controlled access to RT scheduling by unprivileged
   applications (e.g., per-user âquotasâ)
- Monitoring (e.g., residual runtime, available bandwidth)
- Integration/interaction with power management
   (e.g., spec of per-cpu-frequency budget)

How can we guarantee extensibility (or replacement) of parameters in the 
future ?

What about something like _attr_*() in POSIX-like interfaces ?

    T.

--
Tommaso Cucinotta, Computer Engineering PhD, Researcher
ReTiS Lab, Scuola Superiore Sant'Anna, Pisa, Italy
Tel +39 050 882 024, Fax +39 050 882 003
http://retis.sssup.it/people/tommaso

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