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1.1 Multi-Processing and Real-time Ap-proaches
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1.2 Real-time With Linux
2.1 Partition of the Processors and Pro-cesses
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load
balancingload
balancing
cluster
migrationARTiS
migrationARTiS
RT1+
RT CPURT CPURT CPUNRT CPU
RT0
Linux
Figure 1. Example of a typical usage of a system based on ARTiS.
The application is separated alongdifferent levels of real-time
priorities. Tasks are moved by the ARTiS mechanisms of migration
andload-balancing.
2.2 Migration Mechanism
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2.3 Load-Balancing Policy
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Timeinter
ruptd
eactiv
ation
interr
uptd
eactiv
ation
interr
uptd
eactiv
ation
interr
uptd
eactiv
ation
interr
uptd
eactiv
ation
Time
NRT CPU
RT CPU
Figure 2. The so-called ping-pong problem. A task running on a
NRT CPU will be migrated by theload-balancer to a, less loaded, RT
CPU. Due to frequent interrupt deactivation, it soon goes back toa
NRT CPU.
forca
sted
deactiv
ation
Timeinter
ruptd
eactiv
ation
interr
uptd
eactiv
ation
interr
uptd
eactiv
ation
interr
uptd
eactiv
ation
interr
uptd
eactiv
ation
Forbidden migration to RT CPU
Figure 3. Period of forbidden migration (hatched rectangle). The
period is deducted from the studyof the previous behavior of the
given task.
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2.4 System and Application Deployment
3.1 Latency Measurement
3.2 Execution Time Variation
Table 1. Maximum Kernel/User latencies of the different
configurations.
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Tmin
Tmin
Tmin
3.3 Load-balancing Observation
Figure 4. Extract of an lb scenario definition
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