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CMakeLists.txt
CMakeLists.txt
 
 
README.md
README.md
 
 
sched_EDF.c
sched_EDF.c
 
 
sched_FP.c
sched_FP.c
 
 
sched_RM.c
sched_RM.c
 
 
sched_RR.c
sched_RR.c
 
 

README.md

Retif Default Plugins Set

This directory contains the implementation for a set of plugins provided by Retif alongside its main components. The plugins enable the functionality of the daemon, which cannot operate if no plugin is loaded, as it implements no actual functionality related to real-time scheduling.

EDF

Requires kernel version greater than 3.14

This plugin implements the EDF scheduling algorithm, which is well known to be optimum for single processor systems. In particular, we implemented a fully-partitioned version of EDF applying a worst-fit task allocation strategy among the CPU cores specified via the RTS Daemon configuration file. This plugin ensures that the task execution will be suspended in case it overpass the runtime parameter provided. A task could specify a runtime greater that the one required and the daemon dinamycally will decide how much budget provide to the task (the minimum is always guaranteed if accepted).

Stricly required parameters:

  • Runtime
  • Period

Other parameters:

  • Runtime desired
  • Deadline

RM

This plugin implements the Rate Monotonic (RM) scheduling algorithm, which is well known to be optimum for single processor systems among FP scheduling algorithms. In particular, it implements a fully-partitioned version of RM applying a worst-fit task allocation strategy on top of the POSIX SCHED_FIFO scheduling policy among the CPU cores specified via the RTS Daemon configuration file. The only required parameter that a real-time task shall declare to be eligible to be scheduled with this plugin is its period.

Stricly required parameters:

  • Period

Other parameters:

  • Runtime
  • Deadline

FP & RR

The Fixed Priority (FP) and Round Robin (RR) plugins serve as wrappers to expose underlying POSIX functionality to applications that use this framework. They respectively provide access to SCHED_FIFO and SCHED_RR scheduling policies and as such the only required parameter that shall be specified to be accepted by either of these plugins is the desired POSIX priority of the task. For this reason, no admission test is performed when submitting a task to these plugins, although a task may still specify other parameters that may be considered by other plugins’ admission tests. Both plugins apply a worst- fit task allocation strategy, in this case resulting in each new task to be assigned to the CPU core with the least number of assigned tasks.

Stricly required parameters:

  • Priority