Re: Considerations on sched APIs under RT patch

Peter Zijlstra
2010-04-22T13:57:08Z

On Thu, 2010-04-22 at 15:50 +0200, Primiano Tucci wrote:
> I knew this kind of solution based on OS-partitioning, but my group
> and I are currently working on a Global-EDF scheduler, a unique
> scheduler (and therefore a unique OS/Kernel) that is able to migrate
> tasks between CPUs in order to maximize the global CPU usage.

I would hardly call a global-edf scheduler unique. Its a well studied
algorithm and even available in commercial SMP operating systems
(hopefully soon Linux too, see SCHED_DEADLINE, which will approximate
global-edf, much like the current SCHED_FIFO approximates global-fifo).

> In order to to this we have a unique "super"-process (a
> Meta-Scheduler) that needs to be able to control priority and affinity
> of the managed tasks, without losing the control while doing this.

Implementing this as userspace/middleware seems daft. But if your
controlling process has a global affinity mask and runs as the highest
available userspace process priority its still all valid.