The implementation of CPU reservation server

Udo A. Steinberg udo at
Sun May 31 20:32:33 CEST 2009

On Mon, 1 Jun 2009 01:57:46 +0800 Sean (S) wrote:

S> Function l4_rt_generic() is implemented by inline assembly, and it seems
S> to call the system call "thread_schedule".


S>      Because these functions only appears in ARCH-x86 directory, do they
S> support on ARM architecture?

Currently these functions are available on x86 only.

S>      If not, how can I implement similar behaviors of these functions?
S>      Where can I find the document about the L4 system call API ? I can't
S> really understand the behavior of these functions.

The API is described in my diploma thesis, see

You would have to extend the kernel ABI (e.g., which parameters are passed
in which registers) for ARM to be able to use these extensions. Note that
the real-time scheduling code in Fiasco is quite dated. No one has used or
maintained it in the last 5 years.

S> 2. When system contains three user threads, I want to control Fiasco
S> scheduler not to schedule one thread in these three threads during one
S> time interval. How can I implement it?
S>     The simplest way seems to control this thread into un-running state.
S> How can I achieve this by a supervisal server?

I suggest you read the aforementioned PDF document first. It describes how
you can control thread execution with periods, deadlines and release times.


	- Udo
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