1. Partitioned Scheduling of Multimode Systems on Multiprocessor Platforms: when to do the Mode Transition?
José Marinho, Gurulingesh Raravi, Vincent Nélis and Stefan Petters
CISTER – ISEP Research Unit

2. Multi-mode systems Mode 1 Mode 2 MCR D transition time bound
System is composed of set of modes
Each mode is composed of a set of tasks with timing requirements
Mode transition triggered by an MCR
Mode transitions have to complete in a bounded time interval
The length of this interval has to smaller than a given value (mode transition deadline)
Mode 1
Mode 2
MCR
Define MCR, tau 4 collour is messy. Be more explicit on what is a mode D
transition time bound
José Marinho

3. Partitioned Multi-mode
Each processor treated as a bin
For each mode a partitioning table exists
Cores operate mode transitions independently
Mode transition can be handled with single-core protocols straightforwardly
Idle time protocol is still valid (simplest protocol) Π1 Π2
Mode 1 Π1 Π2
Mode 2
Jose Marinho

4. Mode Independent tasks (MIT)
A task may belong to more than one mode
The temporal behaviour can not be perturbed by a mode change between two modes for which the task is common
Task may be in the same partition across common modes
Single-core protocols may be used
Mode transitions core- independent Π1 Π2
Mode 1
MIT Π1 Π2
Define MIT in the text and refer it
Mode 2
Jose Marinho

5. Partitioned Multi-mode with MIT
MIT task may not be in the same partition
Only feasible partition assignment may lead to this
Bin packing algorithm may blindly create the situation
mode changes will require task migration Π1 Π2
τ5 U=0.1
τ2 U=0.46
τ3 U=0.4
Mode 1
τ1 U=0.51
τ4 U=0.5 Π1 Π2
τ3 U=0.4
τ2 U=0.46
Mode 2
τ4 U=0.5
τ6 U=0.6
Jose Marinho

6. Transition Example Mention why this is different from single core
Jose Marinho

7. Discussion
Global scheduling during the mode transition is required when task migration exist
Some Multi-mode task-sets with MIT may not need migrations at all
Create a sufficient test to check if migrations are not needed
Derive resource augmentation bound
Bin packing procedure system-wide that ensures no task migration or minimizes migrations
Remove unfeasible mode transitions
Jose Marinho

8. Discussion
Global scheduling during the mode transition is required when task migration exist
Some Multi-mode task-sets with MIT may not need migrations at all
Create a sufficient test to check if migrations are not needed
Track the maximum admissible interference of MIT’s
Derive resource augmentation bound
Is task migration sufficient or would job migration be more efficient
Bin packing procedure system-wide that ensures no task migration or minimizes migrations
Remove unfeasible mode transitions
Jose Marinho